33 CFR 165.156 - Regulated Navigation Area: East Rockaway Inlet to Atlantic Beach Bridge, Nassau County, Long...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Rockaway Inlet to Atlantic Beach Bridge, Nassau County, Long Island, New York. 165.156 Section 165.156... to Atlantic Beach Bridge, Nassau County, Long Island, New York. (a) Location. The following area is a..., thence easterly along the shore to the east side of the Atlantic Beach Bridge, State Route 878, over East...

33 CFR 165.156 - Regulated Navigation Area: East Rockaway Inlet to Atlantic Beach Bridge, Nassau County, Long...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Rockaway Inlet to Atlantic Beach Bridge, Nassau County, Long Island, New York. 165.156 Section 165.156... to Atlantic Beach Bridge, Nassau County, Long Island, New York. (a) Location. The following area is a..., thence easterly along the shore to the east side of the Atlantic Beach Bridge, State Route 878, over East...

Long-Term Trends, Variability and Extremes of In Situ Sea Surface Temperature Measured Along the Eastern Adriatic Coast and its Relationship to Hemispheric Processes

NASA Astrophysics Data System (ADS)

Grbec, Branka; Matić, Frano; Beg Paklar, Gordana; Morović, Mira; Popović, Ružica; Vilibić, Ivica

2018-02-01

This paper examines long-term series of in situ sea surface temperature (SST) data measured at nine coastal and one open sea stations along the eastern Adriatic Sea for the period 1959-2015. Monthly and yearly averages were used to document SST trends and variability, while clustering and connections to hemispheric indices were achieved by applying the Principal Component Analysis (PCA) and Self-Organizing Maps (SOM) method. Both PCA and SOM revealed the dominance of temporal changes with respect to the effects of spatial differences in SST anomalies, indicating the prevalence of hemispheric processes over local dynamics, such as bora wind spatial inhomogeneity. SST extremes were connected with blocking atmospheric patterns. A substantial warming between 1979 and 2015, in total exceeding 1 °C, was preceded by a period with a negative SST trend, implying strong multidecadal variability in the Adriatic. The strongest connection was found between yearly SST and the East Atlantic (EA) pattern, while North Atlantic Oscillation (NAO) and East Atlantic/West Russia (EAWR) patterns were found to also affect February SST values. Quantification of the Adriatic SST and their connection to hemispheric indices allow for more precise projections of future SST, considered to be rather important for Adriatic thermohaline circulation, biogeochemistry and fisheries, and sensitive to ongoing climate change.

Influence of the Summer NAO on the Spring-NAO-Based Predictability of the East Asian Summer Monsoon

NASA Astrophysics Data System (ADS)

Zheng, Fei

2017-04-01

The dominant mode of atmospheric circulation over the North Atlantic region is the North Atlantic Oscillation (NAO). The boreal spring NAO may imprint its signal on contemporaneous sea surface temperature (SST), leading to a North Atlantic SST tripolar pattern (NAST). This pattern persists into the following summer and modulates the East Asian summer monsoon (EASM). Previous studies have shown that the summer NAST is caused mainly by the preceding spring NAO, whereas the contemporaneous summer NAO plays a secondary role. The results of this study illustrate that, even if the summer NAO plays a secondary role, it may also perturb summer SST anomalies caused by the spring NAO. There are two types of perturbation caused by the summer NAO. If the spring and summer NAO patterns have the same (opposite) polarities, the summer NAST tends to be enhanced (reduced) by the summer NAO, and the correlation between the spring NAO and EASM is usually stronger (weaker). In the former (latter) case, the spring-NAO-based prediction of the EASM tends to have better (limited) skill. These results indicate that it is important to consider the evolution of the NAO when forecasting the EASM, particular when there is a clear reversal in the polarity of the NAO, because it may impair the spring-NAO-based EASM prediction.

Combined effect of the East Atlantic/West Russia and Western Pacific teleconnections on the East Asian winter monsoon

NASA Astrophysics Data System (ADS)

Oh, Hyoeun; Jhun, Jong-Ghap; Ha, Kyung-Ja; Seo, Kyong-Hwan

2017-05-01

This study investigates the individual effects of the East Atlantic/West Russia (EATL/WRUS) and Western Pacific (WP) teleconnection patterns and their combined effect on the East Asian winter monsoon (EAWM). The contributions of the respective EATL/WRUS and WP teleconnection patterns to the EAWM are revealed by removing the dependence on the Arctic Oscillation (AO) and the El Niño-Southern Oscillation (ENSO) using a linear regression, which are named as N_EATL/WRUS and N_WP, respectively. This is because the EATL/WRUS (WP) is closely linked to the Arctic (tropics) region. A significant increase (decrease) in temperature over East Asia (EA) corresponding to a weak (strong) EAWM is associated with the N_EATL/WRUS and N_WP teleconnection patterns during the positive (negative) phases. In order to examine impacts of these two teleconnections on the EAWM, three types of effects are reconstructed on the basis of ± 0.5 standard deviation: 1) Combined effect, 2) N_EATL/WRUS effect, and 3) N_WP effect. The positive N_EATL/WRUS teleconnection induces to a weakened Siberian High and a shallow EA trough at the mid-troposphere through wave propagation, leading to the weak EAWM. During the positive N_WP pattern, warm air from the tropics flows toward the EA along western flank of an anomalous anticyclone over the North Pacific that is relevant to the meridional shift of the Aleutian Low. When the two mid-latitude teleconnections have the in-phase combination, the increase in temperature over EA appears to be more pronounced than the individual effects by transporting warm air from tropics via strong southeasterly wind anomalies induced by anomalous zonal pressure gradient between the Siberian High and Aleutian Low. Therefore, the impact of the mid-latitude teleconnections on the EAWM becomes robust and linearly superimposed, unlike a nonlinear in-phase combined effect of the AO and ENSO.

Spatiotemporal drought variability in the Mediterranean over the last 900 years

NASA Astrophysics Data System (ADS)

Cook, B.; Anchukaitis, K. J.; Touchan, R.; Meko, D. M.; Cook, E. R.

2016-12-01

Recent Mediterranean droughts have highlighted concerns that climate change may be contributing to observed drying trends, but natural climate variability in the region is still poorly understood. We analyze 900 years (1100-2012) of Mediterranean drought variability in the Old World Drought Atlas (OWDA), a spatiotemporal tree ring reconstruction of the June-July-August self-calibrating Palmer Drought Severity Index. In the Mediterranean, the OWDA is highly correlated with spring precipitation (April-June), the North Atlantic Oscillation (January-April), the Scandinavian Pattern (January-March), and the East Atlantic Pattern (April-June). Drought variability displays significant east-west coherence across the basin on multidecadal to centennial timescales and north-south antiphasing in the eastern Mediterranean, with a tendency for wet anomalies in the Black Sea region (e.g., Greece, Anatolia, and the Balkans) when coastal Libya, the southern Levant, and the Middle East are dry, possibly related to the North Atlantic Oscillation. Recent droughts are centered in the western Mediterranean, Greece, and the Levant. Events of similar magnitude in the western Mediterranean and Greece occur in the OWDA, but the recent 15 year drought in the Levant (1998-2012) is the driest in the record. Estimating uncertainties using a resampling approach, we conclude that there is an 89% likelihood that this drought is drier than any comparable period of the last 900 years and a 98% likelihood that it is drier than the last 500 years. These results confirm the exceptional nature of this drought relative to natural variability in recent centuries, consistent with studies that have found evidence for anthropogenically forced drying in the region.

Spatiotemporal drought variability in the Mediterranean over the last 900 years.

PubMed

Cook, Benjamin I; Anchukaitis, Kevin J; Touchan, Ramzi; Meko, David M; Cook, Edward R

2016-03-16

Recent Mediterranean droughts have highlighted concerns that climate change may be contributing to observed drying trends, but natural climate variability in the region is still poorly understood. We analyze 900 years (1100-2012) of Mediterranean drought variability in the Old World Drought Atlas (OWDA), a spatiotemporal tree-ring reconstruction of the June-July-August self calibrating Palmer Drought Severity Index. In the Mediterranean, the OWDA is highly correlated with spring precipitation (April-June), the North Atlantic Oscillation (January-April), the Scandinavian Pattern (January-March), and the East Atlantic Pattern (April-June). Drought variability displays significant east-west coherence across the basin on multi-decadal to centennial time scales and north-south anti-phasing in the eastern Mediterranean, with a tendency for wet anomalies in the Black Sea region (e.g., Greece, Anatolia, the Balkans, etc) when coastal Libya, the southern Levant, and the Middle East are dry, possibly related to the North Atlantic Oscillation. Recent droughts are centered in the Western Mediterranean, Greece, and the Levant. Events of similar magnitude in the Western Mediterranean and Greece occur in the OWDA, but the recent 15-year drought in the Levant (1998-2012) is the driest in the record. Estimating uncertainties using a resampling approach, we conclude there is an 89% likelihood this drought is drier than any comparable period of the last 900 years and a 98% likelihood it is drier than the last 500 years. These results confirm the exceptional nature of this drought relative to natural variability in recent centuries, consistent with studies that have found evidence for anthropogenically forced drying in the region.

Predicting summer monsoon of Bhutan based on SST and teleconnection indices

NASA Astrophysics Data System (ADS)

Dorji, Singay; Herath, Srikantha; Mishra, Binaya Kumar; Chophel, Ugyen

2018-02-01

The paper uses a statistical method of predicting summer monsoon over Bhutan using the ocean-atmospheric circulation variables of sea surface temperature (SST), mean sea-level pressure (MSLP), and selected teleconnection indices. The predictors are selected based on the correlation. They are the SST and MSLP of the Bay of Bengal and the Arabian Sea and the MSLP of Bangladesh and northeast India. The Northern Hemisphere teleconnections of East Atlantic Pattern (EA), West Pacific Pattern (WP), Pacific/North American Pattern, and East Atlantic/West Russia Pattern (EA/WR). The rainfall station data are grouped into two regions with principal components analysis and Ward's hierarchical clustering algorithm. A support vector machine for regression model is proposed to predict the monsoon. The model shows improved skills over traditional linear regression. The model was able to predict the summer monsoon for the test data from 2011 to 2015 with a total monthly root mean squared error of 112 mm for region A and 33 mm for region B. Model could also forecast the 2016 monsoon of the South Asia Monsoon Outlook of World Meteorological Organization (WMO) for Bhutan. The reliance on agriculture and hydropower economy makes the prediction of summer monsoon highly valuable information for farmers and various other sectors. The proposed method can predict summer monsoon for operational forecasting.

Observational evidence of European summer weather patterns predictable from spring

NASA Astrophysics Data System (ADS)

Ossó, Albert; Sutton, Rowan; Shaffrey, Len; Dong, Buwen

2018-01-01

Forecasts of summer weather patterns months in advance would be of great value for a wide range of applications. However, seasonal dynamical model forecasts for European summers have very little skill, particularly for rainfall. It has not been clear whether this low skill reflects inherent unpredictability of summer weather or, alternatively, is a consequence of weaknesses in current forecast systems. Here we analyze atmosphere and ocean observations and identify evidence that a specific pattern of summertime atmospheric circulation––the summer East Atlantic (SEA) pattern––is predictable from the previous spring. An index of North Atlantic sea-surface temperatures in March–April can predict the SEA pattern in July–August with a cross-validated correlation skill above 0.6. Our analyses show that the sea-surface temperatures influence atmospheric circulation and the position of the jet stream over the North Atlantic. The SEA pattern has a particularly strong influence on rainfall in the British Isles, which we find can also be predicted months ahead with a significant skill of 0.56. Our results have immediate application to empirical forecasts of summer rainfall for the United Kingdom, Ireland, and northern France and also suggest that current dynamical model forecast systems have large potential for improvement.

Implications for anomalous mantle pressure and dynamic topography from lithospheric stress patterns in the North Atlantic Realm

NASA Astrophysics Data System (ADS)

Schiffer, Christian; Nielsen, Søren Bom

2016-08-01

With convergent plate boundaries at some distance, the sources of the lithospheric stress field of the North Atlantic Realm are mainly mantle tractions at the base of the lithosphere, lithospheric density structure and topography. Given this, we estimate horizontal deviatoric stresses using a well-established thin sheet model in a global finite element representation. We adjust the lithospheric thickness and the sub-lithospheric pressure iteratively, comparing modelled in plane stress with the observations of the World Stress Map. We find that an anomalous mantle pressure associated with the Iceland and Azores melt anomalies, as well as topography are able to explain the general pattern of the principle horizontal stress directions. The Iceland melt anomaly overprints the classic ridge push perpendicular to the Mid Atlantic ridge and affects the conjugate passive margins in East Greenland more than in western Scandinavia. The dynamic support of topography shows a distinct maximum of c. 1000 m in Iceland and amounts <150 m along the coast of south-western Norway and 250-350 m along the coast of East Greenland. Considering that large areas of the North Atlantic Realm have been estimated to be sub-aerial during the time of break-up, two components of dynamic topography seem to have affected the area: a short-lived, which affected a wider area along the rift system and quickly dissipated after break-up, and a more durable in the close vicinity of Iceland. This is consistent with the appearance of a buoyancy anomaly at the base of the North Atlantic lithosphere at or slightly before continental breakup, relatively fast dissipation of the fringes of this, and continued melt generation below Iceland.

East and central farming and forest region and Atlantic basin diversified farming region: LRRs N and S

Treesearch

Brad D. Lee; John M. Kabrick

2017-01-01

The central, unglaciated US east of the Great Plains to the Atlantic coast corresponds to the area covered by LRR N (East and Central Farming and Forest Region) and S (Atlantic Basin Diversified Farming Region). These regions roughly correspond to the Interior Highlands, Interior Plains, Appalachian Highlands, and the Northern Coastal Plains.

The biology and fisheries of European hake, Merluccius merluccius, in the north-east Atlantic.

PubMed

Murua, Hilario

2010-01-01

The aim of this chapter is to review the biology and fishery, including the management, of European hake in the north-east Atlantic. The European hake is widely distributed throughout the north-east Atlantic, from Norway in the north to the Guinea Gulf in the south, and throughout the Mediterranean and Black Sea, being more abundant from the British Isles to the south of Spain. In this area, ICES (International Council for the Exploration of the Sea) recognises the existence of two stocks: the northern stock and the southern stock. Both stocks have been extensively and intensively harvested and since the beginning of the 90s have been considered to be outside safe biological limits. The northern stock, however, is currently considered to lie within safe biological limits. In any case, recovery plans were implemented for the northern stock in 2004 and for the southern stock in 2006. Despite its commercial importance, knowledge of the biology and ecology of the European hake in the North Atlantic is still quite scarce. For example, recent investigations suggest that European hake grows much faster, by a factor of two, than was considered previously. This faster growth also affects the maturity-at-age pattern of hake and the agreed maturity-at-age ogive used in the assessments. European hake is a top predator in the demersal community in the north-east Atlantic area; mainly preying on blue whiting, horse mackerel and other cupleids. In relation to the reproductive biology, European hake is considered to be a batch spawner species with indeterminate fecundity and spawning activity all year round. All these characteristics could, in turn, be interpreted as European hake adopting a more opportunistic life strategy, which is unusual for a gadoid and demersal species, and raises several questions about hake biology and ecology that require further investigation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Large-scale evolution of the central-east Greenland margin: New insights to the North Atlantic glaciation history

NASA Astrophysics Data System (ADS)

Pérez, Lara F.; Nielsen, Tove; Knutz, Paul C.; Kuijpers, Antoon; Damm, Volkmar

2018-04-01

The continental shelf of central-east Greenland is shaped by several glacially carved transverse troughs that form the oceanward extension of the major fjord systems. The evolution of these troughs through time, and their relation with the large-scale glaciation of the Northern Hemisphere, is poorly understood. In this study seismostratigraphic analyses have been carried out to determine the morphological and structural development of this important sector of the East Greenland glaciated margin. The age of major stratigraphic discontinuities has been constrained by a direct tie to ODP site 987 drilled in the Greenland Sea basin plain off Scoresby Sund fan system. The areal distribution and internal facies of the identified seismic units reveal the large-scale depositional pattern formed by ice-streams draining a major part of the central-east Greenland ice sheet. Initial sedimentation along the margin was, however, mainly controlled by tectonic processes related to the margin construction, continental uplift, and fluvial processes. From late Miocene to present, progradational and erosional patterns point to repeated glacial advances across the shelf. The evolution of depo-centres suggests that ice sheet advances over the continental shelf have occurred since late Miocene, about 2 Myr earlier than previously assumed. This cross-shelf glaciation is more pronounced during late Miocene and early Pliocene along Blosseville Kyst and around the Pliocene/Pleistocene boundary off Scoresby Sund; indicating a northward migration of the glacial advance. The two main periods of glaciation were separated by a major retreat of the ice sheet to an inland position during middle Pliocene. Mounded-wavy deposits interpreted as current-related deposits suggest the presence of changing along-slope current dynamics in concert with the development of the modern North Atlantic oceanographic pattern.

Multidecadal Atlantic climate variability and its impact on marine pelagic communities

NASA Astrophysics Data System (ADS)

Harris, Victoria; Edwards, Martin; Olhede, Sofia C.

2014-05-01

A large scale analysis of sea surface temperature (SST) and climate variability over the North Atlantic and its interactions with plankton over the North East Atlantic was carried out to better understand what drives both temperature and species abundance. The spatio-temporal pattern of SST was found to correspond to known climate indices, namely the Atlantic Multidecadal Oscillation (AMO), the East Atlantic Pattern (EAP) and the North Atlantic Oscillation (NAO). The spatial influence of these indices is heterogeneous. Although the AMO is present across all regions, it is most strongly represented in the SST signal in the subpolar gyre region. The NAO instead is strongly weighted in the North Sea and the pattern of its influence is oscillatory in space with a wavelength of approximately 6000 km. Natural oscillations might obscure the influence of climate change effects, making it difficult to determine how much of the variation is attributable to longer term trends. In order to separate the influences of different climate signals the SST signals were decomposed in to spatial and temporal components using principal component analysis (PCA). A similar analysis is carried out on various indicator species of plankton: Calanus finmarchicus, Phytoplankton Colour Index and total copepod abundance, as well as phytoplankton and zooplankton communities. By comparing the two outputs it is apparent that the dominant driver is the recent warming trend, which has a negative influence on C. finmarchicus and total copepods, but has a positive one on phytoplankton colour. However natural oscillations also influence the abundance of plankton, in particular the AMO is a driver of diatom abundance. Fourier principal component analysis, an approach which is novel in terms of the ecological data, was used to analyse the behaviour of various communities averaged over space. The zooplankton community is found to be primarily influenced by climate warming trends. The analysis provides compelling evidence for the hypothesis that cold water species are gradually being replaced by more temperate species in the North Atlantic. This may have detrimental effects for the entire marine ecosystem, by affecting on organisms such as fish larva for example. The second group, a phytoplankton subset consisting primarily of diatom species, is primarily influenced by the AMO rather than the average temperature trend. This result highlights the importance of natural oscillations to certain functional groups, in particular those subgroups which are less directly metabolically affected by changes in temperature.

Bacteriophage sensitivity patterns among bacteria isolated from marine waters

NASA Astrophysics Data System (ADS)

Moebus, K.; Nattkemper, H.

1981-09-01

Phage-host cross-reaction tests were performed with 774 bacterial strains and 298 bacteriophages. The bacteria (bacteriophages) were isolated at different times from water samples collected in the Atlantic Ocean between the European continental shelf and the Sargasso Sea: 733 (258) strains; in the North Sea near Helgoland: 31 (31) strains; and in the Bay of Biscay: 10 (9) strains. Of the Atlantic Ocean bacteria 326 were found to be susceptible to one or more Atlantic Ocean bacteriophage(s). The bacteriophage sensitivity patterns of these bacteria vary considerably, placing 225 of them in two large clusters of bacteriophage-host systems. Taking all into account, 250 of the 326 Atlantic Ocean bacteria are different from each other. This high degree of variation among the bacteria distinguishes microbial populations derived from widely separated eastern and western regions of the Atlantic Ocean. It also sets apart from each other the populations derived from samples collected at successive stations some 200 miles apart, although to a lesser degree. With bacterial populations found from samples collected on the way back and forth between Europe and the Sargasso Sea a gradual change was observed from "western" phage sensitivity patterns to "eastern" ones. Sixty-nine Atlantic Ocean bacteria are sensitive to bacteriophages isolated from the North Sea and the Bay of Biscay; of these only 26 strains are also susceptible to Atlantic Ocean phages. The interpretation of the results is based on the hydrographical conditions prevailing in the northern Atlantic Ocean including the North Sea, and on the assumption that the microbial populations investigated have undergone genetic changes while being transported within water masses from west to east.

Low-frequency climate anomalies, changes in synoptic scale circulation patterns and statistics of extreme events over south-east Poland during the Last Millennium

NASA Astrophysics Data System (ADS)

Slawinska, J. M.; Bartoszek, K.; Gabriel, C. J.

2016-12-01

Long-term predictions of changes in extreme event frequency are of utmost importance due to their high societal and economic impact. Yet, current projections are of limited skills as they rely on satellite records that are relatively short compared to the timescale of interest, and also due to the presence of a significant anthropogenic trend superimposed onto other low-frequency variabilities. Novel simulations of past climates provide unique opportunity to separate external perturbations from internal climate anomalies and to attribute the latter to systematic changes in different types of synoptic scale circulation and distributions of high-frequency events. Here we study such changes by employing the Last Millennium Ensemble of climate simulations carried out with the Community Earth System Model (CESM) at the U.S. National Center for Atmospheric Research, focusing in particular on decadal changes in frequency of extreme precipitation events over south-east Poland. We analyze low-frequency modulations of dominant patterns of synoptic scale circulations over Europe and their dependence on the Atlantic Meridional Overturning Circulation, along with their coupling with the North Atlantic Oscillation. Moreover, we examine whether some decades of persistently anomalous statistics of extreme events can be attributed to externally forced (e.g., via volcanic eruptions) perturbations of the North Atlantic climate. In the end, we discuss the possible linkages and physical mechanisms connecting volcanic eruptions, low-frequency variabilities of North Atlantic climate and changes in statistics of high impact weather, and compare briefly our results with some historical and paleontological records.

New and rare coastal fishes in the Azores islands: occasional events or tropicalization process?

PubMed

Afonso, P; Porteiro, F M; Fontes, J; Tempera, F; Morato, T; Cardigos, F; Santos, R S

2013-08-01

Seven coastal fish species are newly reported for the remote north Atlantic archipelago of the Azores: Mediterranean sand eel Gymnammodytes cicerelus, bar jack Caranx ruber, two-banded seabream Diplodus vulgaris, bastard grunt Pomadasys incisus, unicorn leatherjacket filefish Aluterus scriptus and longspined porcupinefish Diodon holacanthus. The occurrence is also confirmed for 19 species that had been hitherto cited occasionally for the region, totalling a list of two elasmobranchs and 23 teleosts. Diplodus vulgaris, which appears to have recently colonized the islands, as well as roughtail stingray Dasyatis centroura and golden grey mullet Liza aurata, re-cited based on new records, are frequent or common coastal species in the Azores. The remaining 22 species, exceptional or rare in the region, are of tropical or subtropical affinity and find their northernmost distribution limit within the central and north-east Atlantic Ocean precisely in the Azores. This biogeographical pattern contrasts with that of the Azorean coastal fish community and suggests a tropicalization process in the region in line with previous findings of similar patterns across the north-east Atlantic Ocean and the Mediterranean Sea. These novel data from the most isolated archipelago of the North Atlantic Ocean, located in a biogeographic boundary area where colonization opportunities are reduced, reinforce the need for long-term monitoring programmes of coastal fish communities and, in particular, of indicator species groups to improve understanding of the effects of climate change on marine communities. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

The spatial distribution and evolution characteristics of North Atlantic cyclones

NASA Astrophysics Data System (ADS)

Dacre, H.; Gray, S.

2009-09-01

Mid-latitude cyclones play a large role in determining the day-to-day weather conditions in western Europe through their associated wind and precipitation patterns. Thus, their typical spatial and evolution characteristics are of great interest to meteorologists, insurance and risk management companies. In this study a feature tracking algorithm is applied to a cyclone database produced using the Hewson-method of cyclone identification, based on low-level gradients of wet-bulb potential temperature, to produce a climatology of mid-latitude cyclones. The aim of this work is to compare the cyclone track and density statistics found in this study with previous climatologies and to determine reasons for any differences. This method is found to compare well with other cyclone identification methods; the north Atlantic storm track is reproduced along with the major regions of genesis. Differences are attributed to cyclone lifetime and strength thresholds, dataset resolution and cyclone identification and tracking methods. Previous work on cyclone development has been largely limited to case studies as opposed to analysis of climatological data, and does not distinguish between the different stages of cyclone evolution. The cyclone database used in this study allows cyclone characteristics to be tracked throughout the cyclone lifecycle. This enables the evaluation of the characteristics of cyclone evolution for systems forming in different genesis regions and a calculation of the spatial distribution and evolution of these characteristics in composite cyclones. It was found that most of the cyclones that cross western Europe originate in the east Atlantic where the baroclinicity and sea surface temperature gradients are weak compared to the west Atlantic. East Atlantic cyclones also have higher low-level relative vorticity and lower mean sea level pressure at their genesis point than west Atlantic cyclones. This is consistent with the hypothesis that they are secondary cyclones developing on the trailing fronts of pre-existing 'parent' cyclones. Furthermore, it was found that a higher proportion of east Atlantic cyclones are type C cyclones with strong upper-level forcing but weak low-level forcing suggesting that latent energy plays a more important role in their intensification than for west Atlantic cyclones.

The spatial distribution and evolution characteristics of North Atlantic cyclones

NASA Astrophysics Data System (ADS)

Dacre, H.; Gray, S.

2009-04-01

Mid-latitude cyclones play a large role in determining the day-to-day weather conditions in western Europe through their associated wind and precipitation patterns. Thus, their typical spatial and evolution characteristics are of great interest to meteorologists, insurance and risk management companies. In this study a feature tracking algorithm is applied to a cyclone database produced using the Hewson-method of cyclone identification, based on low-level gradients of wet-bulb potential temperature, to produce a climatology of mid-latitude cyclones. The aim of this work is to compare the cyclone track and density statistics found in this study with previous climatologies. This method is found to compare well with other cyclone identification methods; the north Atlantic storm track is reproduced along with the major regions of genesis. Differences are attributed to cyclone lifetime and strength thresholds, dataset resolution and cyclone identification and tracking methods. Previous work on cyclone development has been largely limited to case studies as opposed to analysis of climatological data, and does not distinguish between the different stages of cyclone evolution. The cyclone database used in this study allows cyclone characteristics to be tracked throughout the cyclone lifecycle. This enables the evaluation of the characteristics of cyclone evolution for systems forming in different genesis regions and a calculation of the spatial distribution and evolution of these characteristics in composite cyclones. It was found that most of the cyclones that cross western Europe originate in the east Atlantic where the baroclinicity and sea surface temperature gradients are weak compared to the west Atlantic. East Atlantic cyclones also have higher low-level relative vorticity and lower mean sea level pressure at their genesis point than west Atlantic cyclones. This is consistent with the hypothesis that they are secondary cyclones developing on the trailing fronts of pre-existing 'parent' cyclones. Furthermore, it was found that a higher proportion of east Atlantic cyclones are type C cyclones with strong upper-level forcing but weak low-level forcing suggesting that latent energy plays a more important role in their intensification than for west Atlantic cyclones.

Impact of tropical Atlantic sea-surface temperature biases on the simulated atmospheric circulation and precipitation over the Atlantic region: An ECHAM6 model study

NASA Astrophysics Data System (ADS)

Eichhorn, Astrid; Bader, Jürgen

2017-09-01

As many coupled atmosphere-ocean general circulation models, the coupled Earth System Model developed at the Max Planck Institute for Meteorology suffers from severe sea-surface temperature (SST) biases in the tropical Atlantic. We performed a set of SST sensitivity experiments with its atmospheric model component ECHAM6 to understand the impact of tropical Atlantic SST biases on atmospheric circulation and precipitation. The model was forced by a climatology of observed global SSTs to focus on simulated seasonal and annual mean state climate. Through the superposition of varying tropical Atlantic bias patterns extracted from the MPI-ESM on top of the control field, this study investigates the relevance of the seasonal variation and spatial structure of tropical Atlantic biases for the simulated response. Results show that the position and structure of the Intertropical Convergence Zone (ITCZ) across the Atlantic is significantly affected, exhibiting a dynamically forced shift of annual mean precipitation maximum to the east of the Atlantic basin as well as a southward shift of the oceanic rain belt. The SST-induced changes in the ITCZ in turn affect seasonal rainfall over adjacent continents. However not only the ITCZ position but also other effects arising from biases in tropical Atlantic SSTs, e.g. variations in the wind field, change the simulation of precipitation over land. The seasonal variation and spatial pattern of tropical Atlantic SST biases turns out to be crucial for the simulated atmospheric response and is essential for analyzing the contribution of SST biases to coupled model mean state biases. Our experiments show that MPI-ESM mean-state biases in the Atlantic sector are mainly driven by SST biases in the tropical Atlantic while teleconnections from other basins seem to play a minor role.

33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... tributary to the Gulf of Mexico east and south of St. Marks, Fla.; use, administration, and navigation. (a... Atlantic Ocean south of Chesapeake Bay or with the Gulf of Mexico east and south of St. Marks, Florida. (2...

33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... tributary to the Gulf of Mexico east and south of St. Marks, Fla.; use, administration, and navigation. (a... Atlantic Ocean south of Chesapeake Bay or with the Gulf of Mexico east and south of St. Marks, Florida. (2...

33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... tributary to the Gulf of Mexico east and south of St. Marks, Fla.; use, administration, and navigation. (a... Atlantic Ocean south of Chesapeake Bay or with the Gulf of Mexico east and south of St. Marks, Florida. (2...

Analysis of the long-term surface wind variability over complex terrain using a high spatial resolution WRF simulation

NASA Astrophysics Data System (ADS)

Jiménez, Pedro A.; González-Rouco, J. Fidel; Montávez, Juan P.; García-Bustamante, E.; Navarro, J.; Dudhia, J.

2013-04-01

This work uses a WRF numerical simulation from 1960 to 2005 performed at a high horizontal resolution (2 km) to analyze the surface wind variability over a complex terrain region located in northern Iberia. A shorter slice of this simulation has been used in a previous study to demonstrate the ability of the WRF model in reproducing the observed wind variability during the period 1992-2005. Learning from that validation exercise, the extended simulation is herein used to inspect the wind behavior where and when observations are not available and to determine the main synoptic mechanisms responsible for the surface wind variability. A principal component analysis was applied to the daily mean wind. Two principal modes of variation accumulate a large percentage of the wind variability (83.7%). The first mode reflects the channeling of the flow between the large mountain systems in northern Iberia modulated by the smaller topographic features of the region. The second mode further contributes to stress the differentiated wind behavior over the mountains and valleys. Both modes show significant contributions at the higher frequencies during the whole analyzed period, with different contributions at lower frequencies during the different decades. A strong relationship was found between these two modes and the zonal and meridional large scale pressure gradients over the area. This relationship is described in the context of the influence of standard circulation modes relevant in the European region like the North Atlantic Oscillation, the East Atlantic pattern, East Atlantic/Western Russia pattern, and the Scandinavian pattern.

A Decadal-scale Air-sea Interaction Theory for North Atlantic Multidecadal Variability: the NAT-NAO-AMOC-AMO Coupled Mode and Its Remote Influences

NASA Astrophysics Data System (ADS)

Li, Jianping; Sun, Cheng; Jin, Fei-Fei

2017-04-01

ABSTRACT North Atlantic region shows prominent multidecadal variability. Observational analysis shows that the North Atlantic Oscillation (NAO) leads the oceanic Atlantic Multidecadal Oscillation (AMO) by 15-20 years and the latter also leads the former by around 15 years. The mechanisms are investigated using simulations from a fully coupled model, and a NATNAO-AMOC-AMO Coupled Mode is proposed to explain the multidecadal variability in North Atlantic region. The NAT-NAO-AMO-AMOC coupled mode has important remote influences on regional climates. Observational analysis identifies a significant in-phase relationship between the AMV and Siberian warm season (May to October) precipitation. The physical mechanism for this relationship is investigated using both observations and numerical simulations. North Atlantic sea surface temperature (SST) warming associated with the positive AMV phase can excite an eastward propagating wave train response across the entire Eurasian continent, which includes an east-west dipole structure over Siberia. The dipole then leads to anomalous southerly winds bringing moisture northward to Siberia; the precipitation increases correspondingly. Furthermore, a prominent teleconnection pattern of multidecadal variability of cold season (November to April) upper-level atmospheric circulation over North Africa and Eurasia (NA-EA) is revealed by empirical orthogonal function analysis of the Twentieth Century Reanalysis data, and this teleconnection pattern is referred to as the Africa-Asia multidecadal teleconnection pattern (AAMT). A strong inphase relationship is observed between the AAMT and Atlantic multidecadal variability (AMV) and this connection is mainly due to Rossby wave dynamics. The AAMT acts as an atmospheric bridge conveying the influence of AMV onto the downstream multidecadal climate variability.

A Preliminary Study of Genetic Variation in Populations of Monstera adansonii var. klotzschiana (Araceae) from North-East Brazil, Estimated with AFLP Molecular Markers

PubMed Central

Andrade, I. M.; Mayo, S. J.; van den Berg, C.; Fay, M. F.; Chester, M.; Lexer, C.; Kirkup, D.

2007-01-01

Background and Aims This study sought genetic evidence of long-term isolation in populations of Monstera adansonii var. klotzschiana (Araceae), a herbaceous, probably outbreeding, humid forest hemi-epiphyte, in the brejo forests of Ceará (north-east Brazil), and clarification of their relationships with populations in Amazonia and the Atlantic forest of Brazil. Methods Within-population genetic diversity and between-population dissimilarity were estimated using AFLP molecular markers in 75 individuals from eight populations located in Ceará, the Brazilian Atlantic Forest and Amazonia. Key Results The populations showed a clinal pattern of weak genetic differentiation over a large geographical region (FST = 0·1896). A strong correlation between genetic and geographical distance (Mantel test: r = 0·6903, P = 0·002) suggests a historical pattern of isolation by distance. Genetic structure analysis revealed at least two distinct gene pools in the data. The two isolated Ceará populations are significantly different from each other (pairwise ΦPT = 0·137, P = 0·003) and as diverse (Nei's gene diversity, average He = 0·1832, 0·1706) as those in the Atlantic and Amazon forest regions. The population in southern Brazil is less diverse (Nei's gene diversity, average He = 0·127) than the rest. The Ceará populations are related to those of the Atlantic forest rather than those from Amazonia (AMOVA, among-groups variation = 11·95 %, P = 0·037). Conclusions The gene pools detected within an overall pattern of clinal variation suggest distinct episodes of gene flow, possibly correlated with past humid forest expansions. The Ceará populations show no evidence of erosion of genetic diversity, although this was expected because of their isolation. Their genetic differentiation and relatively high diversity reinforce the importance of conserving the endangered brejo forests. PMID:17823112

Vicariance, long-distance dispersal, and regional extinction-recolonization dynamics explain the disjunct circumpolar distribution of the arctic-alpine plant Silene acaulis.

PubMed

Gussarova, Galina; Allen, Geraldine A; Mikhaylova, Yulia; McCormick, Laurie J; Mirré, Virginia; Marr, Kendrick L; Hebda, Richard J; Brochmann, Christian

2015-10-01

Many arctic-alpine species have vast geographic ranges, but these may encompass substantial gaps whose origins are poorly understood. Here we address the phylogeographic history of Silene acaulis, a perennial cushion plant with a circumpolar distribution except for a large gap in Siberia. We assessed genetic variation in a range-wide sample of 103 populations using plastid DNA (pDNA) sequences and AFLPs (amplified fragment length polymorphisms). We constructed a haplotype network and performed Bayesian phylogenetic analyses based on plastid sequences. We visualized AFLP patterns using principal coordinate analysis, identified genetic groups using the program structure, and estimated genetic diversity and rarity indices by geographic region. The history of the main pDNA lineages was estimated to span several glaciations. AFLP data revealed a distinct division between Beringia/North America and Europe/East Greenland. These two regions shared only one of 17 pDNA haplotypes. Populations on opposite sides of the Siberian range gap (Ural Mountains and Chukotka) were genetically distinct and appear to have resulted from postglacial leading-edge colonizations. We inferred two refugia in North America (Beringia and the southern Rocky Mountains) and two in Europe (central-southern Europe and northern Europe/East Greenland). Patterns in the East Atlantic region suggested transoceanic long-distance dispersal events. Silene acaulis has a highly dynamic history characterized by vicariance, regional extinction, and recolonization, with persistence in at least four refugia. Long-distance dispersal explains patterns across the Atlantic Ocean, but we found no evidence of dispersal across the Siberian range gap. © 2015 Botanical Society of America.

Population genetic structure in Atlantic and Pacific Ocean common murres (Uria aalge): Natural replicate tests of post-Pleistocene evolution

USGS Publications Warehouse

Morris-Pocock, J. A.; Taylor, S.A.; Birt, T.P.; Damus, M.; Piatt, John F.; Warheit, K.I.; Friesen, Vicki L.

2008-01-01

Understanding the factors that influence population differentiation in temperate taxa can be difficult because the signatures of both historic and contemporary demographics are often reflected in population genetic patterns. Fortunately, analyses based on coalescent theory can help untangle the relative influence of these historic and contemporary factors. Common murres (Uria aalge) are vagile seabirds that breed in the boreal and low arctic waters of the Northern Hemisphere. Previous analyses revealed that Atlantic and Pacific populations are genetically distinct; however, less is known about population genetic structure within ocean basins. We employed the mitochondrial control region, four microsatellite loci and four intron loci to investigate population genetic structure throughout the range of common murres. As in previous studies, we found that Atlantic and Pacific populations diverged during the Pleistocene and do not currently exchange migrants. Therefore, Atlantic and Pacific murre populations can be used as natural replicates to test mechanisms of population differentiation. While we found little population genetic structure within the Pacific, we detected significant east-west structuring among Atlantic colonies. The degree that population genetic structure reflected contemporary population demographics also differed between ocean basins. Specifically, while the low levels of population differentiation in the Pacific are at least partially due to high levels of contemporary gene flow, the east-west structuring of populations within the Atlantic appears to be the result of historic fragmentation of populations rather than restricted contemporary gene flow. The contrasting results in the Atlantic and Pacific Oceans highlight the necessity of carefully considering multilocus nonequilibrium population genetic approaches when reconstructing the demographic history of temperate Northern Hemisphere taxa. ?? 2008 The Authors.

Modulation of the Aleutian-Icelandic Low Seesaw and Its Surface Impacts by the Atlantic Multidecadal Oscillation

NASA Astrophysics Data System (ADS)

Li, F.; Orsolini, Y. J.

2017-12-01

Early studies suggested that the Aleutian-Icelandic low seesaw (AIS) features multidecadal variation. In this study, the multidecadal modulation of the AIS and associated surface climate by the Atlantic Multidecadal Oscillation (AMO) during late winter (February-March) is explored with observational data. It is shown that, in the cold phase of the AMO (AMO|-), a clear AIS is established, while this is not the case in the warm phase of the AMO (AMO|+). The surface climate over Eurasia is significantly influenced by the AMO's modulation of the Aleutian low (AL). For example, the weak AL in AMO|- displays warmer surface temperatures over the entire Far East and along the Russian Arctic coast and into Northern Europe, but only over the Russian Far East in AMO|+. Similarly, precipitation decreases over central Europe with the weak AL in AMO|-, but decreases over northern Europe and increases over southern Europe in AMO|+. The mechanism underlying the influence of AMO|- on the AIS can be described as follows: AMO|- weakens the upward component of the Eliassen-Palm flux along the polar waveguide by reducing atmospheric blocking occurrence over the Euro-Atlantic sector, and hence drives an enhanced stratospheric polar vortex. With the intensified polar night jet, the wave trains originating over the central North Pacific can propagate horizontally through North America and extend into the North Atlantic, favoring an eastward-extended Pacific-North America-Atlantic pattern, and resulting in a significant AIS at the surface during late winter.

Modulation of the Aleutian-Icelandic low seesaw and its surface impacts by the Atlantic Multidecadal Oscillation

NASA Astrophysics Data System (ADS)

Li, Fei; Orsolini, Yvan J.; Wang, Huijun; Gao, Yongqi; He, Shengping

2018-01-01

Early studies suggested that the Aleutian-Icelandic low seesaw (AIS) features multidecadal variation. In this study, the multidecadal modulation of the AIS and associated surface climate by the Atlantic Multidecadal Oscillation (AMO) during late winter (February-March) is explored with observational data. It is shown that, in the cold phase of the AMO (AMO|-), a clear AIS is established, while this is not the case in the warm phase of the AMO (AMO|+). The surface climate over Eurasia is significantly influenced by the AMO's modulation of the Aleutian low (AL). For example, the weak AL in AMO|- displays warmer surface temperatures over the entire Far East and along the Russian Arctic coast and into Northern Europe, but only over the Russian Far East in AMO|+. Similarly, precipitation decreases over central Europe with the weak AL in AMO|-, but decreases over northern Europe and increases over southern Europe in AMO|+. The mechanism underlying the influence of AMO|- on the AIS can be described as follows: AMO|- weakens the upward component of the Eliassen-Palm flux along the polar waveguide by reducing atmospheric blocking occurrence over the Euro-Atlantic sector, and hence drives an enhanced stratospheric polar vortex. With the intensified polar night jet, the wave trains originating over the central North Pacific can propagate horizontally through North America and extend into the North Atlantic, favoring an eastward-extended Pacific-North America-Atlantic pattern, and resulting in a significant AIS at the surface during late winter.

Possible mechanisms for four regimes associated with cold events over East Asia

NASA Astrophysics Data System (ADS)

Yang, Zifan; Huang, Wenyu; Wang, Bin; Chen, Ruyan; Wright, Jonathon S.; Ma, Wenqian

2017-09-01

Circulation patterns associated with cold events over East Asia during the winter months of 1948-2014 are classified into four regimes by applying a k-means clustering method based on the area-weighted pattern correlation. The earliest precursor signals for two regimes are anticyclonic anomalies, which evolve into Ural and central Siberian blocking-like circulation patterns. The earliest precursor signals for the other two regimes are cyclonic anomalies, both of which evolve to amplify the East Asian trough (EAT). Both the blocking-like circulation patterns and amplified EAT favor the initialization of cold events. On average, the blocking-related regimes tend to last longer. The lead time of the earliest precursor signal for the central Siberian blocking-related regime is only 4 days, while those for the other regimes range from 16 to 18 days. The North Atlantic Oscillation plays essential roles both in triggering the precursor for the Ural blocking-related regime and in amplifying the precursors for all regimes. All regimes preferentially occur during the positive phase of the Eurasian teleconnection pattern and the negative phase of the El Niño-Southern Oscillation. For three regimes, surface cooling is primarily due to reduced downward infrared radiation and enhanced cold advection. For the remaining regime, which is associated with the southernmost cooling center, sensible and latent heat release and horizontal cold advection dominate the East Asian cooling.

Impact Of Resolving Submesoscale Features On Modeling The Gulf Stream System

NASA Astrophysics Data System (ADS)

Chassignet, E.; Xu, X.

2016-02-01

Despite being one the best-known circulation pattern of the world ocean, the representation of the Gulf Stream, especially its energetic extension east of the New England Seamounts Chains in the western North Atlantic Ocean, has been a major challenge for ocean general circulation models even at eddy-rich resolutions. Here we show that, for the first time, a simulation of the North Atlantic circulation at 1/50° resolution realistically represents the narrow, energetic jet near 55°W when compared to observations, whereas similarly configured simulations at 1/25° and 1/12° resolution do not. This result highlights the importance of submesoscale features in driving the energetic Gulf Stream extension in the western North Atlantic. The results are discussed in terms of mesoscale and submesoscale energy power spectra.

The changing relationship between the December North Atlantic Oscillation and the following February East Asian trough before and after the late 1980s

NASA Astrophysics Data System (ADS)

Feng, Guolin; Zou, Meng; Qiao, Shaobo; Zhi, Rong; Gong, Zhiqiang

2018-03-01

This study investigates the changing relationship between the December North Atlantic Oscillation (NAO) and the following February East Asian trough (EAT) throughout the past 60 years. We found that the relationship between the December NAO and the following February EAT is significantly enhanced after the late 1980s compared with the period before the late 1980s. The changing relationship mainly results from the enhanced relationship between the December NAO and the following February North Atlantic mid-latitudes' sea surface temperature (SST) anomalies (NAMA) during the same period. During the period after the late 1980s, the persistent positive (negative) NAO pattern from December to the following January contributes to a positive (negative) NAMA, which reaches its maximum magnitude in the following February and excites an anomalous wave train along the North Atlantic and northern Eurasia, and significantly impacts the EAT. During the period before the late 1980s, the positive (negative) NAO pattern during December cannot persist into the following January, and the related positive (negative) NAMA is insignificant during the following February, causing the response of the simultaneous EAT to be insignificant as well. Moreover, there exists a significant impact of the December NAO on the December-January NAMA after the late 1980s, while the December-January NAMA is relatively less affected by the December NAO before the late 1980s. As a result, the simultaneous response of the atmospheric circulation anomalies to the December-January NAMA are evident before the late 1980s, and the positive (negative) NAMA can excite an anomalous wave train along the North Atlantic and northern Eurasia and significantly deepen (shallow) the downstream EAT. By contrast, after involving a feature of atmosphere forcing of SST, the simultaneous feedback of the December-January NAMA on EAT is significantly decreased after the 1980s.

Interdecadal change of the controlling mechanisms for East Asian early summer rainfall variation around the mid-1990s

NASA Astrophysics Data System (ADS)

Yim, So-Young; Wang, Bin; Kwon, MinHo

2014-03-01

East Asian (EA) summer monsoon shows considerable differences in the mean state and principal modes of interannual variation between early summer (May-June, MJ) and late summer (July-August, JA). The present study focuses on the early summer (MJ) precipitation variability. We find that the interannual variation of the MJ precipitation and the processes controlling the variation have been changed abruptly around the mid-1990s. The rainfall anomaly represented by the leading empirical orthogonal function has changed from a dipole-like pattern in pre-95 epoch (1979-1994) to a tripole-like pattern in post-95 epoch (1995-2010); the prevailing period of the corresponding principal component has also changed from 3-5 to 2-3 years. These changes are concurrent with the changes of the corresponding El Nino-Southern Oscillation (ENSO) evolutions. During the pre-95 epoch, the MJ EA rainfall anomaly is coupled to a slow decay of canonical ENSO events signified by an eastern Pacific warming, which induces a dipole rainfall feature over EA. On the other hand, during the post-95 epoch the anomalous MJ EA rainfall is significantly linked to a rapid decay of a central Pacific warming and a distinct tripolar sea surface temperature (SST) in North Atlantic. The central Pacific warming-induced Philippine Sea anticyclone induces an increased rainfall in southern China and decreased rainfall in central eastern China. The North Atlantic Oscillation-related tripolar North Atlantic SST anomaly induces a wave train that is responsible for the increase northern EA rainfall. Those two impacts form the tripole-like rainfall pattern over EA. Understanding such changes is important for improving seasonal to decadal predictions and long-term climate change in EA.

A Teleconnection between the West Siberian Plain and the ENSO Region

NASA Astrophysics Data System (ADS)

Liess, S.; Agrawal, S.; Chatterjee, S.; Kumar, V.

2017-12-01

This study presents a mechanism that links the El Niño/Southern Oscillation (ENSO) to extratropical waves that are deflected from the Northern Hemisphere polar regions and travel southeastward over Central Asia toward the west Pacific warm pool during northern winter. The initial wave pattern resembles the well-known East Atlantic-West Russia pattern. Here we show its influence on the ENSO region. We identify a tripole pattern between the West Siberian Plain and the two centers of action of ENSO with a graph-based approach. It indicates that the background state of ENSO with respect to global sea level pressure (SLP) has a significant negative correlation to the West Siberian Plain. The correlation with the background state, which is defined by the sum of the two centers of action of ENSO, is higher than each of the pairwise correlations with either of the ENSO centers alone. We define the centers with a clustering algorithm that detects regions with similar characteristics. The normalized monthly SLP time series for the two centers of ENSO (around Darwin, Australia and Tahiti) are area-averaged and the sum of both regions is considered as the background state of ENSO. This wave train can be detected throughout the troposphere and the lower stratosphere. Its origins can be traced back to atmospheric wave activity triggered by convection over the subtropical North Atlantic that emanates wave activity toward the West Siberian Plain. The same wave train also propagates to the central Pacific Ocean around Tahiti and can be used to predict the background state over the ENSO region. This background state also modifies the subtropical bridge between the tropical east Pacific and the subtropical North Atlantic, thus leading to a circumglobal wave train.

A Possible Cause for Recent Decadal Atlantic Meridional Overturning Circulation Decline

NASA Astrophysics Data System (ADS)

Latif, Mojib; Park, Taewook; Park, Wonsun

2017-04-01

The Atlantic Meridional Overturning Circulation (AMOC) is a major oceanic current system with widespread climate impacts. AMOC influences have been discussed among others with regard to Atlantic hurricane activity, regional sea level variability, and surface air temperature and precipitation changes on land areas adjacent to the North Atlantic Ocean. Most climate models project significant AMOC slowing during the 21st century, if atmospheric greenhouse gas concentrations continue to rise unabatedly. Recently, a marked decadal decline in AMOC strength has been observed, which was followed by strongly reduced oceanic poleward heat transport and record low sea surface temperature in parts of the North Atlantic. Here, we provide evidence from observations, re-analyses and climate models that the AMOC decline was due to the combined action of the North Atlantic Oscillation and East Atlantic Pattern, the two leading modes of North Atlantic atmospheric surface pressure variability, which prior to the decline both transitioned into their negative phases. This change in atmospheric circulation diminished oceanic heat loss over the Labrador Sea and forced ocean circulation changes lowering upper ocean salinity transport into that region. As a consequence, Labrador Sea deep convection weakened, which eventually slowed the AMOC. This study suggests a new mechanism for decadal AMOC variability, which is important to multiyear climate predictability and climate change detection in the North Atlantic sector.

The effects of depth, distance, and the Mid-Atlantic Ridge on genetic differentiation of abyssal and hadal isopods (Macrostylidae)

NASA Astrophysics Data System (ADS)

Riehl, Torben; Lins, Lidia; Brandt, Angelika

2018-02-01

The largest habitat on Earth, the abyssal oceans below 3500 m depth, is commonly assumed to represent a continuous environment due to homogeneity of environmental factors and the lack of physical barriers. Yet, the presence of bathymetric features, such as Mid-Ocean Ridges, and hadal trenches provide a discontinuation. During the Vema-TRANSIT expedition in 2014/2015 to the tropical North Atlantic, a transatlantic transect was studied following the full extent of the Vema Fracture Zone in an east-west direction and including the Puerto Rico Trench (PRT). The aim of this study was to test whether large bathymetric features represent barriers to dispersal and may lead to differentiation and eventually speciation. In this study, these potential barriers included the Mid-Atlantic Ridge (MAR) and the transition ( 3000 m) from the hadal PRT to the adjacent abyss. Genetic differentiation and differences in community structure (species composition) from east and west of the MAR, as well as abyssal and hadal depth zones were tested for using the poor dispersers Macrostylidae (Crustacea, Isopoda) as a model Distribution patterns showed that certain macrostylid species have ranges extending more than 2000 km, in some cases across oceanic ridges and trench-abyss transitions. Contrastingly, there was a clear signal for geographic population structure coinciding with the east-west division of the Atlantic by the MAR as well as with the abyss-hadal zonation. These results support the hypotheses that depth gradients as well as oceanic ridges reduce dispersal even though barriers may not be absolute. Additionally, positive correlation between genetic- and geographic distances showed that the vast size of the deep sea itself is a factor responsible for creating diversity.

A proposed drainage evolution model for Central Africa—Did the Congo flow east?

NASA Astrophysics Data System (ADS)

Stankiewicz, Jacek; de Wit, Maarten J.

2006-01-01

Understanding the origin of Sub-Saharan biodiversity requires knowing the history of the region's paleo-ecosystems. As water is essential for sustaining of life, the evolving geometry of river basins often have influence on local speciation. With this in mind, we analyse drainage patterns in Central and East Africa. Evidence from marine fossils suggests the Congo Basin was submerged for much of the Cretaceous, and after being uplifted drained eastwards through a paleo-Congo river towards the Indian Ocean. Two remnant peneplains in the Congo Basin are interpreted as evidence that this basin was tectonically stable on at least two occasions in the past. The lower peneplain is interpreted as the base level of the drainage pattern that had its outlet in Tanzania, at the present Rufiji Delta that was once over 500 km wide. The Luangwa, today a tributary of the Zambezi river, was a part of this drainage network. This pattern was subsequently disrupted by uplift associated with the East African Rifting in the Oligocene-Eocene (30-40 Ma). The resulting landlocked system was captured in the Miocene (5-15 Ma) by short rivers draining into the Atlantic Ocean, producing the drainage pattern of Central Africa seen today.

Winter temperatures over the Korean Peninsula and East Asia: development of a new index and its application to seasonal forecast

NASA Astrophysics Data System (ADS)

Kim, Seon Tae; Sohn, Soo-Jin; Kug, Jong-Seong

2017-09-01

This study proposes a new index for monitoring and predicting winter temperatures of the Korean Peninsula based on the dominant atmospheric winter teleconnection patterns. The utilization of this index is further extended to the East Asian Winter Monsoon (EAWM) index because the new index is found to well represent the main feature of the EAWM circulation. Among the teleconnection patterns, the East Atlantic (EA) and Western Pacific (WP) patterns are found to be most strongly correlated with winter temperatures via their partial association with changes in sea level pressure (SLP) around the Korean Peninsula, i.e., the EA and WP patterns are associated with SLP variation over the Siberian High region and the Kuroshio extension region to the east of Japan, respectively. On the basis of this relationship, the two regions representing the northwest-to-southeast SLP gradients are determined to define the new index. It is found that the new index can represent the Korean winter temperatures consistently well regardless of their considerable decadal changes. When compared with the existing SLP-based EAWM indices, the new index shows the best performance in delineating winter air temperatures, not only in the Korean Peninsula but also in the entire East Asian region. We also assess the prediction skill of the new index with seasonal coupled forecast models of the APEC Climate Center of Korea and its capability to predict winter temperatures. This assessment shows that the new index has potential for operationally predicting and monitoring winter temperatures in Korea and the whole of East Asia.

Composition and structure of the parasite faunas of cod, Gadus morhua L. (Teleostei: Gadidae), in the North East Atlantic.

PubMed

Perdiguero-Alonso, Diana; Montero, Francisco E; Raga, Juan Antonio; Kostadinova, Aneta

2008-07-18

Although numerous studies on parasites of the Atlantic cod, Gadus morhua L. have been conducted in the North Atlantic, comparative analyses on local cod parasite faunas are virtually lacking. The present study is based on examination of large samples of cod from six geographical areas of the North East Atlantic which yielded abundant baseline data on parasite distribution and abundance. A total of 826 fish was sampled in the Baltic, Celtic, Irish and North seas, Icelandic waters and Trondheimsfjord (Norway) in 2002 (spring and autumn) and 2003 (spring). The gills and internal organs (oesophagus, stomach, intestine, pyloric caeca, liver, heart, spleen, gall bladder and gonads) were examined for macroparasites following a standardised protocol. The taxonomic consistency of the identification was ensured thorough the entire study. We discuss some problems in parasite identification, outline the composition of the parasite faunas in cod in the six North East Atlantic regions, provide novel data on parasite prevalence and abundance and a comparative assessment of the structure of the regional parasite faunas with respect to the higher-level taxonomic groupings, host specificity and zoogeographical distribution of the parasites. Altogether 57 different parasite forms were found including seven new host records (Diclidophora merlangi, Rhipidocotyle sp., Fellodistomum sp., Steringotrema sp., Cucullanus sp., Spinitectus sp., and Chondracanthus ornatus). The predominant groups of cod parasites were trematodes (19 species) and nematodes (13 species) including larval anisakids which comprised 58.2% of the total number of individuals. Our study reveals relatively rich regional parasite faunas in cod from the North East Atlantic which are dominated by generalist parasites with Arcto-Boreal distribution. Further, it provides more detailed data on the distribution in the North East Atlantic of the majority of cod parasites which may serve as baselines for future studies on the effect of climate change. Based on the faunal comparisons, predictions can be made in relation to the structure and diversity of the parasite communities in the North East Atlantic regions studied.

East-looking view across Atlantic waters during MA-9 22 orbit

NASA Technical Reports Server (NTRS)

1963-01-01

East looking view across Atlantic waters toward Africa, showing Mauritania and Spanish Sahara photographed from the Mercury-Atlas 9 capsule by Astronaut L. Gordon Cooper Jr., during his 22 orbit Mercury-Atlas 9 (MA-9) spaceflight.

Water-Level Changes in Aquifers of the Atlantic Coastal Plain, Predevelopment to 2000

USGS Publications Warehouse

dePaul, Vincent T.; Rice, Donald E.; Zapecza, Otto S.

2008-01-01

The Atlantic Coastal Plain aquifer system, which underlies a large part of the east coast of the United States, is an important source of water for more than 20 million people. As the population of the region increases, further demand is being placed on those ground-water resources. To define areas of past and current declines in ground-water levels, as well as to document changes in those levels, historical water-level data from more than 4,000 wells completed in 13 regional aquifers in the Atlantic Coastal Plain were examined. From predevelopment to 1980, substantial water-level declines occurred in many areas of the Atlantic Coastal Plain. Regional variability in water-level change in the confined aquifers of the Atlantic Coastal Plain resulted from regional differences in aquifer properties and patterns of ground-water withdrawals. Within the Northern Atlantic Coastal Plain, declines of more than 100 ft were observed in New Jersey, Delaware, Maryland, Virginia, and North Carolina. Regional declines in water levels were most widespread in the deeper aquifers that were most effectively confined?the Upper, Middle, and Lower Potomac aquifers. Within these aquifers, water levels had declined up to 200 ft in southern Virginia and to more than 100 ft in New Jersey, Delaware, Maryland, and North Carolina. Substantial water-level declines were also evident in the regional Lower Chesapeake aquifer in southeastern New Jersey; in the Castle Hayne-Piney Point aquifer in Delaware, Maryland, southern Virginia and east-central North Carolina; in the Peedee-Severn aquifer in east-central New Jersey and southeastern North Carolina; and in the Black Creek-Matawan aquifer in east-central New Jersey and east-central North Carolina. Conversely, declines were least severe in the regional Upper Chesapeake aquifer during this period. In the Southeastern Coastal Plain, declines of more than 100 ft in the Chattahoochee River aquifer occurred in eastern South Carolina and in southwestern Georgia, where water levels had declined approximately 140 and 200 ft from prepumping conditions, respectively. Within the Upper Floridan aquifer, decline was most pronounced in the coastal areas of Georgia and northern Florida where ground-water withdrawals were at their highest. These areas included Savannah, Jesup, and Brunswick, Ga., as well as the St. Marys, Ga. and Fernandina Beach, Fla., area. Regional water levels had declined by 80 ft near Brunswick and Fernandina Beach to as much as 160 ft near Savannah. Since 1980, water levels in many areas have continued to fall; however, in some places the rate at which levels declined has slowed. Conservation measures have served to limit withdrawals in affected areas, moderating or stabilizing water-level decline, and in some cases, resulting in substantial recovery. In other cases, increases in ground-water pumpage have resulted in continued rapid decline in water levels. From 1980 to 2000, water levels across the regional Upper, Middle, and Lower Potomac aquifers continued to decline across large parts of Delaware, Maryland, Virginia, and North Carolina, and water levels had stabilized or recovered throughout much of Long Island and New Jersey. Substantial water-level recovery had also occurred in east-central New Jersey in the Peedee-Severn and Black Creek-Matawan aquifers and in east-central North Carolina in the Castle Hayne-Piney Point aquifer. Substantial declines from about 1980 to about 2000 occurred in the Peedee-Severn aquifer in southern New Jersey, the Beaufort-Aquia aquifer in southern Maryland, and the Black Creek-Matawan and Upper Potomac aquifers in central and southern parts of the coastal plain in North Carolina. From 1980 to about 2000, water levels within the regional Upper Floridan aquifer had generally stabilized in response to shifting withdrawal patterns and reductions in pumpage at many places within the coastal region. Ground-water levels had stabilized and recovered at the ma

Assessing the role of Climate Variability in the recent evolution of coastlines in southern Italy

NASA Astrophysics Data System (ADS)

Di Paola, Gianluigi; Atkinson, David; Rosskopf, Carmen M.; Walker, Ian

2016-04-01

During the last century, Climatic Variability (CV) and change effects have generated a discernable impact on the world's coasts, most notably through changes in the frequency and/or magnitude of storm surges, flooding, coastal erosion and sea-level rise. This study explores CV signals and coastal responses along a 36 km stretch of coast in the Molise region of southern Italy on the Central Adriatic Sea. Two dominant signals of CV in the Mediterranean region of Europe are characterized by the North Atlantic Oscillation (NAO) and the East Atlantic-West Russia (EAWR) patterns. The NAO is the leading mode of CV in the North Atlantic region and periods with positive NAO index values are typically associated with above average wind speeds across the mid-latitudes of the Atlantic and western Europe, with anomalously northerly flows across the Mediterranean region and enhanced trade winds over the sub-tropical North Atlantic. Although NAO is one of the most prominent patterns in all seasons, its relative role in regulating the variability of the European climate during non-winter months is not as clear as for the winter season. In contrast, the EAWR exerts strong influence on precipitation in the Mediterranean region such that, during the negative phase of EAWR, wetter conditions prevail across central Europe and the Mediterranean region, with precipitation extremes often occurring during these periods. This study examines the effects of NAO and EAWR on coastline response in the Molise region, which has a microtidal regime (ordinary tidal excursions of 30-40 cm). GIS analysis of shoreline changes from historical aerial photography from 1954-2011 was performed and 20 years (1989-2008) of wave data were analysed from the nearby Ortona buoy to define trends and extreme event occurrence in the wave climate in the study area. Finally, statistical associations between NAO, EAWR, and other CV indices of possible influence (e.g. Arctic Oscillation, Scandinavia Pattern, or the East Atlantic pattern) and shoreline position changes were explored in order to identify linkages between CV forcing and coastal response in this region. The study demonstrates that the recent evolution of the Molise coastline is responding to changes in the wave climate and increases in the frequency and intensity of storm surges in recent years. Coastal response in the region is also strongly controlled by engineering interventions, such as backwater structures and groynes (almost the 75% of coastline is characterized by offshore defenses, above all around Biferno and Trigno mouths and Termoli harbor), and the interaction of the river systems that feed the coastline. This condition may mitigate some of the impacts of CV events that are observed elsewhere along intervening stretches of coast.

33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... the Gulf of Mexico east and south of St. Marks, Fla. (a) Description. This section applies to the... or with the Gulf of Mexico east and south of St. Marks, Florida. (2) United States property. All...

33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... the Gulf of Mexico east and south of St. Marks, Fla. (a) Description. This section applies to the... or with the Gulf of Mexico east and south of St. Marks, Florida. (2) United States property. All...

33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... the Gulf of Mexico east and south of St. Marks, Fla. (a) Description. This section applies to the... or with the Gulf of Mexico east and south of St. Marks, Florida. (2) United States property. All...

Distributions and Changes of Carbonate Parameters Along the U.S. East Coast

NASA Astrophysics Data System (ADS)

Xu, Y. Y.; Cai, W. J.; Wanninkhof, R. H.; Salisbury, J., II

2017-12-01

On top of anthropogenic climate change, upwelling, eutrophication, river discharge, and interactions with the open ocean have affected carbonate chemistry in coastal waters. In this study, we present the large-scale variations of carbonate parameters along the U.S. east coast using in situ observations obtained during an East Coast Ocean Acidification (ECOA) cruise in summer 2015. Compare with previous large-scale cruises along the east coast, the ECOA cruise increases spatial coverage in the Gulf of Marine region and has more offshore stations for a better understanding of carbon dynamics in coastal waters and their interactions with open ocean waters. Our results show that the spatial distribution of water mass properties set up the large-scale advection of salt and heat and the distribution of total alkalinity (TA). However, dissolved inorganic carbon (DIC) shows a distinct pattern. Coastal water pH displays high variability in the Gulf of Maine and the Mid-Atlantic Bight (MAB). But it is relatively homogeneous in the South Atlantic Bight (SAB). In contrast, the distribution of aragonite saturation state (Ω) has an increase pattern from north to south similar to those of TA, SST, and SSS. A mechanistic discussion will be presented to understand the controls on Ω in eastern coastal waters. A comparison with previous cruises also suggests very different changes of pH and Ω in the MAB and SAB. Preliminary analysis suggests an overall increase in surface pH and Ω in the MAB. In contrast, pH and Ω in the SAB surface waters decrease over the past two decades. This work serves as a platform for the monitoring of large-scale carbon cycling in the U.S. east coast. It is also important to identify the physical and biogeochemical processes that affect these distributions and changes over time for a better understanding of carbon cycling and ocean acidification in coastal waters.

The Impact of Trends in the Large Scale Atmospheric Circulation on Mediterranean Surface Turbulent Heat Fluxes

NASA Technical Reports Server (NTRS)

Romanski, Joy; Hameed, Sultan

2015-01-01

Interannual variations of latent heat fluxes (LHF) and sensible heat fluxes (SHF) over the Mediterranean for the boreal winter season (DJF) show positive trends during 1958-2011. Using reanalysis and satellite-based products, the variability and trends in the heat fluxes are compared with variations in three atmospheric teleconnection patterns: the North Atlantic Oscillation (NAO), the pressure and position of the Azores High (AH), and the East Atlantic-West Russia teleconnection pattern (EAWR). Comparison of correlations between the heat fluxes and teleconnections, along with analysis of composites of surface temperature, humidity, and wind fields for different teleconnection states, demonstrates that the AH explains the heat flux changes more successfully than NAO and EAWR. Trends in pressure and longitude of the Azores High show a strengthening and an eastward shift. Variations of the Azores High occur along an axis defined by lower pressure and westward location at one extreme and higher pressure and eastward location at the other extreme. The shift of the AH from predominance of the low/west state to the high/east state induces trends in Mediterranean Sea surface winds, temperature, and moisture. These, combined with sea surface warming trends, produce trends in wintertime sensible and latent heat fluxes.

Characteristics of tropical cyclones in the North Atlantic and East Pacific

NASA Astrophysics Data System (ADS)

Barrett, Bradford Scott

In this dissertation, I present a series of investigations to expand our understanding of TCs in the East Pacific and North Atlantic basins. First, I developed and applied a climatological tool that quickly and succinctly displays the spread of historical TC tracks for any point in the North Atlantic basin. This tool is useful in all parts of a basin because it is derived from prior storm motion trajectories and summarily captures the historical synoptic and mesoscale steering patterns. It displays the strength of the climatological signal and allow for rapid qualitative comparison between historical TC tracks and NWP models. Second, I have used a robust statistical technique to quantify the relationships between fifteen different metrics of TC activity in nine ocean basins and twelve climate indices of the leading modes of atmospheric and oceanic variability. In a thorough, encyclopedic manner, over 12,000 Spearman rank correlation coefficients were calculated and examined to identify relationships between TCs and their environment. This investigation was not limited to the East Pacific or North Atlantic, and new climatic associations were found between seasonal levels of TC activity and the major climate indices across the nine basins. This information is critical to forecasters, economists, actuaries, energy traders, and societal planners who apply knowledge of levels of TC activity on intraseasonal to interdecadal timescales. The statistics are also valuable to climatologists seeking to understand how regional TC frequency will change as the global climate warms. Third, I have examined the leading intraseasonal mode of atmospheric and oceanic variability, the Madden-Julian Oscillation (MJO), and discovered statistically significant relationships with the frequency of TC genesis, intensification, and landfall over the nine basins. Like the significance of the longer-period oscillations to the frequency of TC activity on intraseasonal and longer timescales, these results are highly relevant to the problem of short-term (one- to two-week) predictability of TC activity. These three investigations demonstrate the utility of historical datasets across a wide range of applications, from short-term forecasting to climate studies. In this way, the results highlighted in this dissertation represent a significant and positive contribution to meteorology. Collectively, they reveal multiple characteristics of TCs in the East Pacific and North Atlantic and provide greater understanding of the complex interactions between TCs and their surrounding larger-scale environment.

Past and future impact of North Atlantic teleconnection patterns on the hydroclimate of the Caspian catchment area in CESM1.2.2 and observations

NASA Astrophysics Data System (ADS)

Nandini, Sri

2017-04-01

The Caspian Sea level has undergone dramatic variations of more than 3 m during the past century with important implications for the life of coastal people, economy and the ecosystem. The origin of these variations as well as future changes in the Caspian water budget are still a matter of debate. In this study, we examine the influence of the major seasonal North Atlantic teleconnection patterns, the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the Scandinavian pattern (SCA), and the North Sea Caspian Pattern (NCP), on Caspian hydroclimate variability from 1850-2000 CE. Numerical experiments at different atmospheric grid resolutions (2° and 1°) are carried out with the coupled Community Earth System Model (CESM1.2.2). We test model skills under different resolutions through validation against observational data by various statistical methods (Empirical Orthogonal Functions, Taylor diagrams, linear regressions and Spearman rank correlation). Results reveal the strongest simulated signal in winter (DJF) with high explained variances for 1° CESM1.2.2 NAO (39%) and EA (15.7%), similar to observational data. The model is unable to reproduce the SCA pattern in the third EOF, which is found in the observations. The modelled NAO has a strong influence on winter temperature and rainfall over the Caspian catchment area. A strong winter NCP induces above-average 2-meter temperatures over north Caspian region and lower-than-normal precipitation over the eastern Caspian sea. Our study suggests that the 1° version of CESM1.2.2 (with CAM5 atmosphere physics) shows adequate performance with respect to teleconnection maps during the historical period. Lastly, 1° model climate projections (2005-2100 CE) are performed with different Representative Concentration Pathways (RCP 4.5 and RCP 8.5) to examine potential changes in the teleconnection patterns and their influence on the Caspian region.

Cold season Africa-Asia multidecadal teleconnection pattern and its relation to the Atlantic multidecadal variability

NASA Astrophysics Data System (ADS)

Sun, Cheng; Li, Jianping; Ding, Ruiqiang; Jin, Ze

2017-06-01

A prominent teleconnection pattern of multidecadal variability of cold season (November to April) upper-level atmospheric circulation over North Africa and Eurasia (NA-EA) is revealed by empirical orthogonal function analysis of the Twentieth Century Reanalysis data. This teleconnection pattern is characterized by an eastward propagating wave train with a zonal wavenumber of 5-6 between 20° and 40°N, extending from the northwest coast of Africa to East Asia, and thus is referred to as the Africa-Asia multidecadal teleconnection pattern (AAMT). One-point correlation maps show that the teleconnectivity of AAMT is strong and further demonstrate the existence of the AAMT. The AAMT shapes the spatial structure of multidecadal change in atmospheric circulation over the NA-EA region, and in particular the AAMT pattern and associated fields show similar structures to the change occurring around the early 1960s. A strong in-phase relationship is observed between the AAMT and Atlantic multidecadal variability (AMV) and this connection is mainly due to Rossby wave dynamics. Barotropic modeling results suggest that the upper-level Rossby wave source generated by the AMV can excite the AAMT wave train, and Rossby wave ray tracing analysis further highlights the role of the Asian jet stream in guiding the wave train to East Asia. The AAMT acts as an atmospheric bridge conveying the influence of AMV onto the downstream multidecadal climate variability. The AMV is closely related to the coordinated change in surface and tropospheric air temperatures over Northwest Africa, the Arabian Peninsula and Central China, which may result from the adiabatic expansion/compression of air associated with the AAMT.

Imprint of the Atlantic Multidecadal Oscillation on Tree-Ring Widths in Northeastern Asia since 1568

PubMed Central

Wang, Xiaochun; Brown, Peter M.; Zhang, Yanni; Song, Laiping

2011-01-01

We present a new tree-ring reconstruction of the Atlantic Multidecadal Oscillation (AMO) spanning 1568–2007 CE from northeast Asia. Comparison of the instrumental AMO index, an existing tree-ring based AMO reconstruction, and this new record show strongly similar annual to multidecadal patterns of variation over the last 440 years. Warm phases of the AMO are related to increases in growth of Scots pine trees and moisture availability in northeast China and central eastern Siberia. Multi-tape method (MTM) and cross-wavelet analyses indicate that robust multidecadal (∼64–128 years) variability is present throughout the new proxy record. Our results have important implications concerning the influence of North Atlantic sea surface temperatures on East Asian climate, and provide support for the possibility of an AMO signature on global multidecadal climate variability. PMID:21818380

Links between teleconnection patterns and mean temperature in Spain

NASA Astrophysics Data System (ADS)

Ríos-Cornejo, David; Penas, Ángel; Álvarez-Esteban, Ramón; del Río, Sara

2015-10-01

This work describes the relationships between Spanish temperature and four teleconnection patterns with influence on the Iberian Peninsula on monthly, seasonal and annual time scales, using data from 144 meteorological stations. Partial correlation analyses were carried out using Spearman test, and spatial distribution maps of the correlation coefficients were produced with geostatistical interpolation techniques. We regionalize the study area based on homogeneous areas containing weather stations with a similar response of temperatures to the same patterns. The links between the temperature and the patterns are mainly positive; only the correlations with Western Mediterranean Oscillation (WeMO) in the north and west are negative, indicating that WeMO plays an opposed role in temperature behaviour in Spain. In general terms, the four modes exert considerable influence on temperature in February, May and September. The East Atlantic (EA) is the pattern with the strongest influence on temperature in Spain—mainly in the north—except in June. Generally, on the seasonal and annual scales, large significant areas were only observed for the EA. EA and WeMO best account for the mean temperature on the Mediterranean fringe and in northern Spain, while EA and North Atlantic Oscillation largely explain the temperature in the rest of Spain.

Mediterranean Thermohaline Response to Large-Scale Winter Atmospheric Forcing in a High-Resolution Ocean Model Simulation

NASA Astrophysics Data System (ADS)

Cusinato, Eleonora; Zanchettin, Davide; Sannino, Gianmaria; Rubino, Angelo

2018-04-01

Large-scale circulation anomalies over the North Atlantic and Euro-Mediterranean regions described by dominant climate modes, such as the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the East Atlantic/Western Russian (EAWR) and the Mediterranean Oscillation Index (MOI), significantly affect interannual-to-decadal climatic and hydroclimatic variability in the Euro-Mediterranean region. However, whereas previous studies assessed the impact of such climate modes on air-sea heat and freshwater fluxes in the Mediterranean Sea, the propagation of these atmospheric forcing signals from the surface toward the interior and the abyss of the Mediterranean Sea remains unexplored. Here, we use a high-resolution ocean model simulation covering the 1979-2013 period to investigate spatial patterns and time scales of the Mediterranean thermohaline response to winter forcing from NAO, EA, EAWR and MOI. We find that these modes significantly imprint on the thermohaline properties in key areas of the Mediterranean Sea through a variety of mechanisms. Typically, density anomalies induced by all modes remain confined in the upper 600 m depth and remain significant for up to 18-24 months. One of the clearest propagation signals refers to the EA in the Adriatic and northern Ionian seas: There, negative EA anomalies are associated to an extensive positive density response, with anomalies that sink to the bottom of the South Adriatic Pit within a 2-year time. Other strong responses are the thermally driven responses to the EA in the Gulf of Lions and to the EAWR in the Aegean Sea. MOI and EAWR forcing of thermohaline properties in the Eastern Mediterranean sub-basins seems to be determined by reinforcement processes linked to the persistency of these modes in multiannual anomalous states. Our study also suggests that NAO, EA, EAWR and MOI could critically interfere with internal, deep and abyssal ocean dynamics and variability in the Mediterranean Sea.

A meteorological overview of the Subsonic Assessment Ozone and Nitrogen Oxide Experiment (SONEX) period

NASA Astrophysics Data System (ADS)

Fuelberg, Henry E.; Hannan, John R.; van Velthoven, Peter F. J.; Browell, Edward V.; Bieberbach, George; Knabb, Richard D.; Gregory, Gerald L.; Pickering, Kenneth E.; Selkirk, Henry B.

2000-02-01

Meteorological conditions are described during NASA's Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX) that was conducted over the North Atlantic Flight Corridor (NAFC) during October and November 1997 to study the impact of aircraft emissions on atmospheric concentrations of NOx and ozone. The SONEX period exhibited frequent closed cyclones and anticyclones, as well as high-amplitude troughs and ridges. These flow patterns often caused aircraft exhaust from the NAFC to follow broad looping north-south trajectories, instead of more easterly routes that would have occurred if the flow had been more zonal. Mean meteorological conditions during SONEX include a pronounced long wave trough over the East Coast of the United States, as well as weaker low pressure over middle-latitude portions of the Atlantic Ocean. Conversely, a well-developed ridge was apparent over the North Atlantic near Iceland. Cloudiness exceeded climatology off the East Coast and the subtropical North Atlantic, with abundant lightning in these regions. There was less than average cloud cover over the middle latitudes between Newfoundland and central Europe. The tropopause was higher than climatology over much of the SONEX region, and the jet stream was located north of its typical position. These circulation features during SONEX are consistent with typical year-to-year variations. Meteorological conditions during individual SONEX flights also are described. Upper tropospheric flow patterns, 5-day backward trajectories from the flight tracks, tropopause heights, lightning data, and differential absorption lidar ozone imagery are employed. Effects of aircraft were observed on numerous flights. Stratospheric conditions were encountered during many flights, sometimes because the DC-8 passed through a tropopause fold. SONEX flight tracks frequently were downwind of regions of lightning, especially during flights from Bangor and the Azores. Finally, trajectories indicated that continental pollution signatures observed during some flights had originated over the United States.

East-looking view across Atlantic waters during MA-9 22 orbit

NASA Image and Video Library

1963-05-16

S63-06434 (15-16 May 1963) --- East looking view across Atlantic waters toward Africa, showing Mauritania and Spanish Sahara photographed from the Mercury-Atlas 9 (MA-9) capsule by astronaut L. Gordon Cooper Jr., during his 22-orbit MA-9 spaceflight. Photo credit: NASA

North Atlantic teleconnection patterns signature on sea level from satellite altimetry

NASA Astrophysics Data System (ADS)

Iglesias, Isabel; Lázaro, Clara; Joana Fernandes, M.; Bastos, Luísa

2015-04-01

Presently, satellite altimetry record is long enough to appropriately study inter-annual signals in sea level anomaly and ocean surface circulation, allowing the association of teleconnection patterns of low-frequency variability with the response of sea level. The variability of the Atlantic Ocean at basin-scale is known to be complex in space and time, with the dominant mode occurring on annual timescales. However, interannual and decadal variability have already been documented in sea surface temperature. Both modes are believed to be linked and are known to influence sea level along coastal regions. The analysis of the sea level multiannual variability is thus essential to understand the present climate and its long-term variability. While in the open-ocean sea level anomaly from satellite altimetry currently possesses centimetre-level accuracy, satellite altimetry measurements become invalid or of lower accuracy along the coast due to the invalidity of the wet tropospheric correction (WTC) derived from on-board microwave radiometers. In order to adequately analyse long-term changes in sea level in the coastal regions, satellite altimetry measurements can be recovered by using an improved WTC computed from recent algorithms that combine wet path delays from all available observations (remote sensing scanning imaging radiometers, GNSS stations, microwave radiometers on-board satellite altimetry missions and numerical weather models). In this study, a 20-year (1993-2013) time series of multi-mission satellite altimetry (TOPEX/Poseidon, Jason-1, OSTM/Jason-2, ERS-1/2, ENVISAT, CryoSat-2 and SARAL), are used to characterize the North Atlantic (NA) long-term variability on sea level at basin-scale and analyse its response to several atmospheric teleconnections known to operate on the NA. The altimetry record was generated using an improved coastal WTC computed from either the GNSS-derived path Delay or the Data Combination methodologies developed by University of Porto (Fernandes et al., 2010; Fernandes et al., 2013). Regular 0.25°x0.25° latitude-longitude grids were generated at a 10-day interval for the NA Ocean (60°W-5°W, 5°N-60°N) using optimal interpolation with a realistic space-time correlation function (Lázaro et al., 2013). These grids are used to inspect the response of sea level anomalies to several teleconnection patterns as well as the NA variability on annual and longer timescales. The teleconnection patterns selected are the ones that have influence on the NA basin: North Atlantic Oscillation, East Atlantic pattern, East Atlantic/Western Russia pattern, Scandinavia pattern, Western Mediterranean Oscillation index, El Niño Southern Oscillation, Tropical North Atlantic Index, and Atlantic Multidecadal Oscillation. Acknowledgments: RAIA tec (0688-RAIATEC-1-P) project. The RAIA Coastal Observatory has been funded by the Programa Operativo de Cooperación Transfronteriza España-Portugal (POCTEP 2007-2013). References: Fernandes M.J., C. Lázaro, A.L. Nunes, N. Pires, L. Bastos, V.B. Mendes (2010). GNSS-derived Path Delay: an approach to compute the wet tropospheric correction for coastal altimetry. IEEE Geosci. Rem. Sens Lett., Vol. 7, NO. 3, 596 - 600, doi: 10.1109/LGRS.2010.2042425. Lázaro, C., M. J. Juliano, M. J. Fernandes (2013): Semi-automatic determination of the Azores Current axis using satellite altimetry: application to the study of the current variability during 1995-2006. Advances in Space Research, Vol. 51(11), pp. 2155-2170, doi:10.1016/j.asr.2012.12.021. Fernandes, M. J., A.L. Nunes, C. Lázaro (2013). Analysis and Inter-Calibration of Wet Path Delay Datasets to Compute the Wet Tropospheric Correction for CryoSat-2 over Ocean. Remote Sensing, 5, 4977-5005.

Combined influences of seasonal East Atlantic Pattern and North Atlantic Oscillation to excite Atlantic multidecadal variability in a climate model

NASA Astrophysics Data System (ADS)

Ruprich-Robert, Yohan; Cassou, Christophe

2015-01-01

The physical processes underlying the internal component of the Atlantic Multidecadal Variability (AMV) are investigated from a 1,000-yr pre-industrial control simulation of the CNRM-CM5 model. The low-frequency fluctuations of the Atlantic Meridional Overturning Circulation (AMOC) are shown to be the main precursor for the model AMV. The full life cycle of AMOC/AMV events relies on a complex time-evolving relationship with both North Atlantic Oscillation (NAO) and East Atlantic Pattern (EAP) that must be considered from a seasonal perspective in order to isolate their action; the ocean is responsible for setting the multidecadal timescale of the fluctuations. AMOC rise leading to a warm phase of AMV is statistically preceded by wintertime NAO+ and EAP+ from ~Lag -40/-20 yrs. Associated wind stress anomalies induce an acceleration of the subpolar gyre (SPG) and enhanced northward transport of warm and saline subtropical water. Concurrent positive salinity anomalies occur in the Greenland-Iceland-Norwegian Seas in link to local sea-ice decline; those are advected by the Eastern Greenland Current to the Labrador Sea participating to the progressive densification of the SPG and the intensification of ocean deep convection leading to AMOC strengthening. From ~Lag -10 yrs prior an AMOC maximum, opposite relationship is found with the NAO for both summer and winter seasons. Despite negative lags, NAO- at that time is consistent with the atmospheric response through teleconnection to the northward shift/intensification of the Inter Tropical Convergence Zone in link to the ongoing warming of tropical north Atlantic basin due to AMOC rise/AMV build-up. NAO- acts as a positive feedback for the full development of the model AMV through surface fluxes but, at the same time, prepares its termination through negative retroaction on AMOC. Relationship between EAP+ and AMOC is also present in summer from ~Lags -30/+10 yrs while winter EAP- is favored around the AMV peak. Based on additional atmospheric-forced experiments, both are interpreted as the local seasonal-dependent atmospheric response to warmer North Atlantic. Finally, advection of fresher water from the tropical basin created by local atmosphere/ocean anomalous circulation on one hand and from the Arctic on the other hand due to large-scale sea ice melting leads to decrease of density in the SPG and contributes terminating the model AMOC/AMV events. All together, the combined effects of NAO and EAP, their intertwined seasonal forcing/forced role upon/by the ocean and the primary role of salinity anomalies associated with oceanic dynamical changes acting as an integrator are responsible in CNRM-CM5 for an irregular and damped mode of variability for AMOC/AMV that takes about 35-40 (15-20) years to build up (dissipate).

Tropical Atlantic-Korea teleconnection pattern during boreal summer season

NASA Astrophysics Data System (ADS)

Ham, Yoo-Geun; Chikamoto, Yoshimitsu; Kug, Jong-Seong; Kimoto, Masahide; Mochizuki, Takashi

2017-10-01

The remote impact of tropical Atlantic sea surface temperature (SST) variability on Korean summer precipitation is examined based on observational data analysis along with the idealized and hindcast model experiments. Observations show a significant correlation (i.e. 0.64) between Korean precipitation anomalies (averaged over 120-130°E, 35-40°N) and the tropical Atlantic SST index (averaged over 60°W-20°E, 30°S-30°N) during the June-July-August (JJA) season for the 1979-2010 period. Our observational analysis and partial-data assimilation experiments using the coupled general circulation model demonstrate that tropical Atlantic SST warming induces the equatorial low-level easterly over the western Pacific through a reorganization of the global Walker Circulation, causing a decreased precipitation over the off-equatorial western Pacific. As a Gill-type response to this diabatic forcing, an anomalous low-level anticyclonic circulation appears over the Philippine Sea, which transports wet air from the tropics to East Asia through low-level southerly, resulting an enhanced precipitation in the Korean peninsula. Multi-model hindcast experiments also show that predictive skills of Korean summer precipitation are improved by utilizing predictions of tropical Atlantic SST anomalies as a predictor for Korean precipitation anomalies.

Variability of sea surface height and circulation in the North Atlantic: Forcing mechanisms and linkages

NASA Astrophysics Data System (ADS)

Wang, Zeliang; Lu, Youyu; Dupont, Frederic; W. Loder, John; Hannah, Charles; G. Wright, Daniel

2015-03-01

Simulations with a coarse-resolution global ocean model during 1958-2004 are analyzed to understand the inter-annual and decadal variability of the North Atlantic. Analyses of Empirical Orthogonal Functions (EOFs) suggest relationships among basin-scale variations of sea surface height (SSH) and depth-integrated circulation, and the winter North Atlantic Oscillation (NAO) or the East Atlantic Pattern (EAP) indices. The linkages between the atmospheric indices and ocean variables are shown to be related to the different roles played by surface momentum and heat fluxes in driving ocean variability. In the subpolar region, variations of the gyre strength, SSH in the central Labrador Sea and the NAO index are highly correlated. Surface heat flux is important in driving variations of SSH and circulation in the upper ocean and decadal variations of the Atlantic Meridional Overturning Circulation (AMOC). Surface momentum flux drives a significant barotropic component of flow and makes a noticeable contribution to the AMOC. In the subtropical region, momentum flux plays a dominant role in driving variations of the gyre circulation and AMOC; there is a strong correlation between gyre strength and SSH at Bermuda.

Is the Great Barracuda (Sphyraena barracuda) a reef fish or a pelagic fish? The phylogeographic perspective

PubMed Central

Randall, John E.; Bowen, Brian W.

2013-01-01

Current taxonomy indicates a single global species of the Great Barracuda (Sphyraena barracuda) despite differences in color and behavior between Atlantic and Pacific forms. To investigate these differences and qualify the dispersal characteristics of this unique coastal– pelagic teleost (bony fish), we conducted a global phylogeographic survey of 246 specimens from thirteen sampling locations using a 629-base pair fragment of mtDNA cytochrome b. Data indicate high overall gene flow in the Indo-Pacific over large distances (>16,500 km) bridging several biogeographic barriers. The West Atlantic population contains an mtDNA lineage that is divergent from the Indo-Pacific (d = 1.9%), while the East Atlantic (N = 23) has two mutations (d = 0.6%) apart from the Indo-Pacific. While we cannot rule out distinct evolutionary partitions among ocean basins based on behavior, coloration, and near-monophyly between Atlantic and Indo-Pacific subpopulations, more investigation is required before taxonomic status is revised. Overall, the pattern of high global dispersal and connectivity in S. barracuda more closely resembles those reported for large oceanic predators than reef-associated teleosts. PMID:25594680

Upper air teleconnections to Ob River flows and tree rings

NASA Astrophysics Data System (ADS)

Meko, David; Panyushkina, Irina; Agafonov, Leonid

2015-04-01

The Ob River, one of the world's greatest rivers, with a catchment basin about the size of Western Europe, contributes 12% or more of the annual freshwater inflow to the Arctic Ocean. The input of heat and fresh water is important to the global climate system through effects on sea ice, salinity, and the thermohaline circulation of the ocean. As part of a tree-ring project to obtain multi-century long information on variability of Ob River flows, a network of 18 sites of Pinus, Larix, Populus and Salix has been collected along the Ob in the summers of 2013 and 2014. Analysis of collections processed so far indicates a significant relationship of tree-growth to river discharge. Moderation of the floodplain air temperature regime by flooding appears to be an important driver of the tree-ring response. In unraveling the relationship of tree-growth to river flows, it is important to identify atmospheric circulation features directly linked to observed time series variations of flow and tree growth. In this study we examine statistical links between primary teleconnection modes of Northern Hemisphere upper-air (500 mb) circulation, Ob River flow, and tree-ring chronologies. Annual discharge at the mouth of the Ob River is found to be significantly positively related to the phase of the East Atlantic (EA) pattern, the second prominent mode of low-frequency variability over the North Atlantic. The EA pattern, consisting of a north-south dipole of pressure-anomaly centers spanning the North Atlantic from east to west, is associated with a low-pressure anomaly centered over the Ob River Basin, and with a pattern of positive precipitation anomaly of the same region. The positive correlation of discharge and EA is consistent with these know patterns, and is contrasted with generally negative (though smaller) correlations between EA and tree-ring chronologies. The signs of correlations are consistent with a conceptual model of river influence on tree growth through air temperature. Future work aims at combining the tree-ring samples from living trees and remnant wood to reconstruction to quantitiative reconstruction of annual flow over the past millennium.

Distinct winter patterns of tropical Pacific convection anomaly and the associated extratropical wave trains in the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Ding, Shuoyi; Chen, Wen; Graf, Hans-F.; Guo, Yuanyuan; Nath, Debashis

2017-11-01

In this paper, distinct patterns of boreal winter convection anomalies over the tropical Pacific and associated wave trains in the extratropics are addressed. The first leading mode (EOF1) of convection anomalies as measured by outgoing longwave radiation demonstrates an east-west oscillation of deep convection with centers over the equatorial central Pacific (CP) and over the tropical western North Pacific and the Maritime Continent. The second leading mode (EOF2) is also a dipole pattern with opposite centers straddling 170°W, possibly modifying EOF1 to some extent. Combining the first two leading modes, five major categories of tropical convection anomalies can be identified for the period 1979/80-2012/13. The comparison between these five categories and the corresponding SST anomaly patterns indicates a nonlinear relationship between convection and SST. The combination of EOF1 and EOF2 with in-phase PCs exhibits an east-west dipole pattern with opposite signs over west of the dateline and the Maritime Continent. The negative phase of the two PCs, named La Niña pattern, induces a negative Pacific/North American—positive North Atlantic Oscillation teleconnection in the extratropics. Approximately opposite responses can be detected in its positive phase, named CP El Niño pattern. The negative PC2 superposing positive PC1, named EP El Niño pattern, shows the strongest convection anomalies with enhanced (depressed) convection over the eastern (western) Pacific and leads to a Tropical/Northern Hemisphere-like teleconnection pattern and an anomalous anticyclone extending from the North Pacific to the North Atlantic. The positive PC2 with neutral PC1, named western CP pattern, shows weakly enhanced convection to the west of the dateline as a response to local SST warming around the dateline. This convection anomaly pattern, although weak, is important and excites a northeastward wave train from the tropics to Greenland, resulting in surface air temperature cooling covering the northeastern North America and warmer and wetter conditions over Western Europe.

Recurrent Interannual Climate Modes and Teleconnection Linking North America Warm Season Precipitation Anomalies to Asia Summer Monsoon Variability

NASA Technical Reports Server (NTRS)

Lau, K. M.; Weng, H. Y.; Einaudi, Franco (Technical Monitor)

2001-01-01

In this paper, we present results showing that summertime precipitation anomalies over North America and East Asia may be linked via pan-Pacific teleconnection patterns, which are components of two dominant recurring global climate modes. The first mode (Mode-1) features an inverse relationship between rainfall anomaly over the US Midwest/central to the eastern/southeastern regions, coupled to a mid-tropospheric high-low pressure system over the northwest and southeast of the US, which regulates low level moisture transport from the Gulf of Mexico to the Midwest. The regional circulation pattern appears to be a part of a global climate mode spanning Eurasia, the North Pacific, North America, and the Atlantic. This mode is associated with coherent fluctuations of jetstream variability over East Asia, and Eurasia, SST in the North Pacific and the North Atlantic. While Mode-1 is moderately correlated with El Nino-Southern Oscillation (ENSO), it appears to be distinct from it, with strong influences from mid-latitude or possibly from higher latitude processes. Results show that Mode-1 not only has an outstanding contribution to the great flood of 1993, it has large contribution to the US precipitation anomalies in other years. Also noted is an apparent increase in influence of Mode-1 on US summertime precipitation in the last two decades since 1977.

Trends in ice formation at Lake Neusiedl since 1931 and large-scale oscillation patterns

NASA Astrophysics Data System (ADS)

Soja, Anna-Maria; Maracek, Karl; Soja, Gerhard

2013-04-01

Ice formation at Lake Neusiedl (Neusiedler See, Fertitó), a shallow steppe lake (area 320 km2, mean depth 1.2 m) at the border of Austria/Hungary, is of ecological and economic importance. Ice sailing and skating help to keep a touristic off-season alive. Reed harvest to maintain the ecological function of the reed belt (178 km2) is facilitated when lake surface is frozen. Changes in ice formation were analysed in the frame of the EULAKES-project (European Lakes under Environmental Stressors, www.eulakes.eu), financed by the Central Europe Programme of the EU. Data records of ice-on, ice duration and ice-off at Lake Neusiedl starting with the year 1931, and air temperature (nearby monitoring station Eisenstadt - Sopron (HISTALP database and ZAMG)) were used to investigate nearly 80 winters. Additionally, influences of 8 teleconnection patterns, i.e. the Atlantic Multidecadal Oscillation (AMO), the East Atlantic pattern (EAP), the East Atlantic/West Russia pattern (EA/WR), the Eastern Mediterranean Pattern (EMP), the Mediterranean Oscillation (MO) for Algiers and Cairo, and for Israel and Gibraltar, resp., the North Atlantic Oscillation (NAO) and the Scandinavia pattern (SCA) were assessed. Ice cover of Lake Neusiedl showed a high variability between the years (mean duration 71±27 days). Significant trends for later ice-on (p=0.02), shorter ice duration (p=0.07) and earlier ice-off (p=0.02) for the period 1931-2011 were found by regression analysis and trend analysis tests. On an average, freezing of Lake Neusiedl started 2 days later per decade and ice melting began 2 days earlier per decade. Close relationships between mean air temperature and ice formation could be found: ice-on showed a dependency on summer (R=+0.28) and autumn air temperatures (R=+0.51), ice duration and ice off was related to autumn (R=-0.36 and -0.24), winter (R=-0.73 and -0.61) and concurrent spring air temperatures (R=-0.44). Increases of air temperature by 1° C caused an 8.4 days later timing of ice-on, a decrease of ice duration by 11.0 days and a 5.8 days earlier ice-off. The sensitivity of ice duration and ice-off to rising air temperatures was increasing at Lake Neusiedl. This effect of warming could not be verified for the timing of ice-on. Ice-on at Lake Neusiedl showed a significant relation to EAP (yearly index; R=0.33). Ice duration and ice-off were influenced significantly by the winter indices of MO for Algiers and Cairo (R=-0.48 and -0.45), NAO (R=-0.42 and -0.37), and EAP (R=-0.31 and -0.48).

Synoptic scale convection and wave activity over tropical Africa and the Atlantic

NASA Astrophysics Data System (ADS)

Mekonnen, Ademe

The objective of this research is to investigate synoptic scale convection and its association with wave disturbances over eastern Atlantic and tropical Africa. Analyses of convection highlight a significant peak periodicity in 2-6 day time scale over the Atlantic and most of tropical North Africa. The 2-6 day convective variance is the same order of magnitude over West and East Africa and accounts for 25%-35% of the total variance. However, dynamical measures of the African easterly wave (AEW) activity showed marked differences, variances over the West being more than the East. The explanation for this is that AEWs are initiated by convective precursors in the east and grow as they propagate westwards along the African easterly jet. Results show two major regions of synoptic time scale convection that are important for AEW initiation: the Darfur mountains (˜20°E) and the Ethiopian highlands (35°-40°E), with the former being more consistent and coherent. This study also shows the presence of eastward moving convective structures over tropical Africa, which are associated with Kelvin waves. The Kelvin waves originate in the Pacific and propagate across Africa. An important aspect of the Kelvin wave activity is its impact on convection and rainfall and its interaction with AEWs. Analysis of July-September 1987 weather events showed that convection and rainfall increase in association with Kelvin waves over tropical Africa. This event also suggested a series of AEWs initiated in association with Kelvin convection over tropical Africa. Spectral analysis of convection indicates a significant 3-4 day periodicity over Central Sudan, a region not known for wave disturbances. Two key factors that are associated with this variance are: (a) convective variability over equatorial Congo, and (b) upper level easterly waves that originate over Bay of Bengal-Southeast Asia. Results show the presence of a dipole pattern between the equatorial and East African convection that oscillates on a 4-day time scale. It is suggested that the two regions interact through a recharge-discharge process. This study also shows that convection over East Africa enhances in association with anomalous northerlies and weakens in association with southerlies in the upper troposphere.

Transport and Fate of Nutrients Along the U.S. East Coast

NASA Astrophysics Data System (ADS)

Hofmann, E. E.; Narvaez, D.; Friedrichs, M. A. M.; Najjar, R.; Tian, H.; Hyde, K.; Mannino, A.; Signorini, S. R.; Wilkin, J.; St-Laurent, P.

2017-12-01

As part of a NASA-funded multi-investigator project, a land-estuarine-ocean biogeochemical modeling system was implemented and verified with remote sensing and in situ data to examine processes controlling fluxes on land, their coupling to riverine systems, the delivery of materials to estuaries and the coastal ocean, and marine ecosystem responses to these changing riverine inputs and changing climate forcing. This modeling system is being used to develop nutrient budgets for the U.S. east coast continental shelf and to examine seasonal and interannual variability in nutrient fluxes. An important aspect of these nutrient budgets is the transport and fate of nutrients released along the inner shelf. Results from a five-year simulation (2004 to 2008) that used tracer releases from the main rivers along the Middle Atlantic Bight (MAB) and South Atlantic Bight (SAB) provide insights into transport pathways that connect the inner and outer continental shelf. Tracers released along the inner MAB spread along the shelf with a general southward and offshore transport. Inner shelf inputs from the large estuarine systems are transported to the mid and outer MAB shelf. Tracers that reach the mid to outer shelf can be entrained in the Gulf Stream. Export from the MAB to the SAB occurs during periods of southerly winds. Transport processes along the SAB are similar, but Gulf Stream entrainment is a larger component of tracer transport. Superimposed on the MAB and SAB transport patterns is considerable seasonal and interannual variability. The results from these retrospective simulations improve understanding of the coupling at the land-water interface and shelf-wide transport patterns that advance the ability to predict the effects of localized human impacts and broader-scale climate-related impacts on the U.S. east coast continental shelf system.

The 2014 southeast Brazil austral summer drought: regional scale mechanisms and teleconnections

NASA Astrophysics Data System (ADS)

Coelho, Caio A. S.; de Oliveira, Cristiano Prestrelo; Ambrizzi, Tércio; Reboita, Michelle Simões; Carpenedo, Camila Bertoletti; Campos, José Leandro Pereira Silveira; Tomaziello, Ana Carolina Nóbile; Pampuch, Luana Albertani; Custódio, Maria de Souza; Dutra, Lívia Marcia Mosso; Da Rocha, Rosmeri P.; Rehbein, Amanda

2016-06-01

The southeast region of Brazil experienced in austral summer 2014 a major drought event leading to a number of impacts in water availability for human consumption, agricultural irrigation and hydropower production. This study aims to perform a diagnostic analysis of the observed climate conditions during this event, including an inspection of the occurred precipitation anomalies in the context of previous years, and an investigation of possible relationships with sea surface temperatures and atmospheric circulation patterns. The sea surface temperature analysis revealed that the southwestern South Atlantic Ocean region near the coast of southeast Brazil showed strong negative association with precipitation over southeast Brazil, indicating that increased sea temperatures in this ocean region are consistent with reduced precipitation as observed in summer 2014. The circulation analysis revealed prevailing anti-cyclonic anomalies at lower levels (850 hPa) with northerly anomalies to the west of southeast Brazil, channeling moisture from the Amazon towards Paraguay, northern Argentina and southern Brazil, and drier than normal air from the South Atlantic Ocean towards the southeast region of Brazil. This circulation pattern was found to be part of a large-scale teleconnection wave train linked with the subsidence branch of the Walker circulation in the tropical east Pacific, which in turn was generated by an anomalous tropical heat source in north/northeastern Australia. A regional Hadley circulation with an ascending branch to the south of the subsidence branch of the Walker circulation in the tropical east Pacific was identified as an important component connecting the tropical and extratropical circulation. The ascending branch of this Hadley circulation in the south Pacific coincided with an identified Rossby wave source region, which contributed to establishing the extratropical component of the large-scale wave train connecting the south Pacific and the Atlantic region surrounding southeast Brazil. This connection between the Pacific and the Atlantic was confirmed with Rossby ray tracing analyses. The local circulation response was associated to downward air motion (subsidence) over Southeast Brazil, contributing to the expressive negative precipitation anomalies observed during summer 2014, and leading to a major drought event in the historical context. The analysis of atmospheric and oceanic patterns of this event helped defining a schematic framework leading to the observed drought conditions in southeast Brazil, including the involved teleconnections, blocking high pressure, radiative and humidity transport effects.

Strong Dependence of U.S. Summertime Air Quality on the Decadal Variability of Atlantic Sea Surface Temperatures

NASA Astrophysics Data System (ADS)

Shen, Lu; Mickley, Loretta J.; Leibensperger, Eric M.; Li, Mingwei

2017-12-01

We find that summertime air quality in the eastern U.S. displays strong dependence on North Atlantic sea surface temperatures, resulting from large-scale ocean-atmosphere interactions. Using observations, reanalysis data sets, and climate model simulations, we further identify a multidecadal variability in surface air quality driven by the Atlantic Multidecadal Oscillation (AMO). In one-half cycle ( 35 years) of the AMO from cold to warm phase, summertime maximum daily 8 h ozone concentrations increase by 1-4 ppbv and PM2.5 concentrations increase by 0.3-1.0 μg m-3 over much of the east. These air quality changes are related to warmer, drier, and more stagnant weather in the AMO warm phase, together with anomalous circulation patterns at the surface and aloft. If the AMO shifts to the cold phase in future years, it could partly offset the climate penalty on U.S. air quality brought by global warming, an effect which should be considered in long-term air quality planning.

78 FR 73499 - Proposed Information Collection; Comment Request; Atlantic Sea Scallops Amendment 10 Data Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-06

... Collection; Comment Request; Atlantic Sea Scallops Amendment 10 Data Collection AGENCY: National Oceanic and... Fisheries Service (NMFS) Northeast Region manages the Atlantic sea scallop (scallop) fishery of the Exclusive Economic Zone (EEZ) off the East Coast under the Atlantic Sea Scallop Fishery Management Plan (FMP...

Varied representation of the West Pacific pattern in multiple dynamical seasonal predictions of APCC-MME

NASA Astrophysics Data System (ADS)

Lee, Yun-Young

2017-04-01

West Pacific (WP) teleconnection pattern is one of the well-known primary modes of boreal winter low-frequency variability (LFV) resolved in 500 hPa geopotential height and its phase and amplitude strongly influence regional weather conditions including temperature and rainfall extremes [Baxter and Nigam, 2015; Hsu and Wallace, 1985; Linkin and Nigam, 2008; Mo and Livezey, 1986; Thompson and Wallace, 1998; Wallace and Gutzler, 1981]. This study primary aims to evaluate individual 11 GCMs seasonal hindcasts employed as members of multi-model ensemble (MME) produced in APEC Climate Center (APCC) in representing WP. For the extensive and comprehensive evaluation, this study applied seven verification metrics in three scopes: (a) temporal representation of observed indices, (b) spatial mode separation in the Northern Hemisphere (NH), and (c) regional mode isolated in the preset longitudinal domain. Verification results display quite large inter-model spread. Some models mimic observed index variability while others display large bias of index variability compared to climatology. Basic north-south dipole pattern is mostly well reproduced in both rotated and unrotated loading modes. However, each individual seasonal forecast model exhibits slightly different behavior (e.g. amplification/weakening, zonal and meridional shift, downstream extension and so forth) in representing spatial structure of WP. When taking all 7 metrics into account, one Europe (CMCC) model, one Oceania (POAMA) model and two North America (NASA and NCEP) models are classified as relatively good performers while PNU is classified as a matchless poor performer out of 11. Least WP representing skill of PNU is sort of consistent with the largest bias of NH total variability. This study further tries to examine winter mean biases of individual models and figure out how mean bias is linked to WP representation in model world. Model bias of winter climatology is investigated focusing on six large scale phenomena: East Asian winter monsoon (EAWM), Atlantic dipole, Pacific/Atlantic jets and Pacific/Atlantic Hadley circulations. Changes in structure and amplitude of them are diagnosed in terms of root mean square error, pattern correlation, intensity bias, zonal displacement and/or downstream extension. There is consistent strengthening/downstream extension of Atlantic jet and absence of southern divergence cell of Atlantic Hadley in most seasonal prediction models. It is demonstrated that WP representation has something to do with bias of Atlantic winter climatology (Atlantic dipole and Atlantic jet) from scatter plot and regression analysis. This implies the importance of realistic simulation of winter climatology further upstream for better WP representation. A fundamental conclusion of this study is that the representation of primary WP features varies among individual models of APCC-MME and it is significantly dependent on the deficiencies of some winter mean climatological patterns.

Migration and winter distributions of canvasbacks staging on the Upper Mississippi River

USGS Publications Warehouse

Serie, J.R.; Trauger, D.L.; Sharp, D.E.

1983-01-01

Fall and winter distribution patterns of canvasbacks (Aythya valisineria) staging on the upper Mississippi River near LaCrosse, Wisconsin (navigational Pools 7 and 8) and Keokuk, Iowa (Pool 19) were studied during 1973-77. Sightings and recoveries obtained from 1,488 color-marked males during 1973-75 and 3,789 banded males and females during 1973-77 suggested 2 principal migration corridors: 1 extending eastward from Pools 7 and 8 to the eastern Great Lakes and southeast to the Mid-Atlantic Region and another southward from Pools 7 and 8 to the lower Mississippi Valley, Gulf Coast, and east Texas regions. These discrete populations stage concurrently on Pools 7 and 8 during the fall, but winter in different areas of the Atlantic, Mississippi, and Central flyways. Populations staging on Pool 19 were not discrete from those staging on Pools 7 and 8. A continual turnover of birds passing through these staging areas was indicated. Canvasbacks wintering in the Mississippi and Central flyways were widely dispersed among a variety of habitats, whereas canvasbacks wintering in the Atlantic Flyway were concentrated in a few traditional habitats. Canvasbacks exhibited strong fidelity to wintering areas. Distribution patterns and population attributes of canvasbacks during fall and winter may be explained by the predictability of natural foods and their ability to exploit these foods.

Impact of the North Atlantic circulation on the climate change patterns of North Sea.

NASA Astrophysics Data System (ADS)

Narayan, Nikesh; Mathis, Mortiz; Klein, Birgit; Klein, Holger; Mikolajewicz, Uwe

2017-04-01

The physical properties of the North Sea are characterized by the exchange of water masses with the North Atlantic at the northern boundary and Baltic Sea to the east. The combined effects of localized forcing, tidal mixing and advection of water masses make the North Sea a challenging study area. Previous investigations indicated a possibility that the variability of the North Atlantic circulation and the strength of the sub-polar gyre (SPG) might influence the physical properties of the North Sea. The assessment of the complex interaction between the North Atlantic and the North Sea in a climate change scenario requires regionally coupled global RCP simulations with enhanced resolution of the North Sea and the North Atlantic. In this study we analyzed result from the regionally coupled ocean-atmosphere-biogeochemistry model system (MPIOM-REMO-HAMOCC) with a hydrodynamic (HD) model. The ocean model has a zoomed grid which provides the highest resolution over the West European Shelf by shifting its poles over Chicago and Central Europe. An index for the intensity of SPG was estimated by averaging the barotropic stream function (ψ) over the North Atlantic. Various threshold values for ψ were tested to define the strength of the SPG. These SPG indices have been correlated with North Sea hydrographic parameters at various levels to identify areas affected by SPG variability. The influence of the Atlantic's eastern boundary current, contributing more saline waters to the North West European shelf area is also investigated.

Glacimarine Sedimentary Processes and Facies on the Polar North Atlantic Margins

NASA Astrophysics Data System (ADS)

Dowdeswell, J. A.; Elverhfi, A.; Spielhagen, R.

Major contrasts in the glaciological, oceanic and atmospheric parameters affecting the Polar North Atlantic, both over space between its eastern and western margins, and through time from full glacial to interglacial conditions, have lead to the deposition of a wide variety of sedimentary facies in these ice-influenced seas. The dynamics of the glaciers and ice sheets on the hinterlands surrounding the Polar North Atlantic have exterted a major influence on the processes, rates and patterns of sedimentation on the continental margins of the Norwegian and Greenland seas over the Late Cenozoic. The western margin is influenced by the cold East Greenland Current and the Svalbard margin by the northernmost extent of the warm North Atlantic Drift and the passage of relatively warm cyclonic air masses. In the fjords of Spitsbergen and the northwestern Barents Sea, glacial meltwater is dominant in delivering sediments. In the fjords of East Greenland the large numbers of icebergs produced from fast-flowing outlets of the Greenland Ice Sheet play a more significant role in sedimentation. During full glacials, sediments are delivered to the shelf break from fast-flowing ice streams, which drain huge basins within the parent ice sheet. Large prograding fans located on the continental slope offshore of these ice streams are made up of stacked debris flows. Large-scale mass failures, turbidity currents, and gas-escape structures also rework debris in continental slope and shelf settings. Even during interglacials, both the margins and the deep ocean basins beyond them retain a glacimarine overprint derived from debris in far-travelled icebergs and sea ice. Under full glacial conditions, the glacier influence is correspondingly stronger, and this is reflected in the glacial and glacimarine facies deposited at these times.

North Atlantic Oscillation Drives Regional Greenland Glacier Volume During the 20th Century

NASA Astrophysics Data System (ADS)

Bjork, A. A.; Aagaard, S.; Hallander, A. M.; Khan, S. A.; Box, J. E.; Kjeldsen, K. K.; Larsen, N. K.; Korsgaard, N. J.; Cappelen, J.; Colgan, W. T.; Machguth, H.; Andresen, C. S.; Kjaer, K. H.

2016-12-01

While most areas of the Greenland ice sheet have undergone rapid mass loss since c. 1990, the central eastern section of the ice sheet has advanced and gained mass. This contrasting regional trend has been attributed to positive surface mass balance (SMB) in the absence of significant dynamic mass loss. To constrain the atypical behavior in this region, we mapped glacier length fluctuations of nearly 200 peripheral glaciers and ice caps (PGICs) over a 103-year period, and compare the results with c. 150 new glacier length records from central west Greenland. We demonstrate that the regional response in ice volume is closely correlated to changes in precipitation, governed by circulation patterns associated with the North Atlantic Oscillation (NAO) and secondarily influenced by temperature forcing in certain periods. More broadly, we find that the NAO contributes to contrasting precipitation variability in East and West Greenland, where it appears to be responsible for at least 10% and more than 25%, respectively, of the variability in ice sheet accumulation rate. This east-west asymmetry, which influences both LGICs and the ice sheet, illustrates how substantial uncertainty in NAO projections directly contributes to uncertainty in mass balance projections.

Meiofauna abundance and community patterns along a transatlantic transect in the Vema Fracture Zone and in the hadal zone of the Puerto Rico trench

NASA Astrophysics Data System (ADS)

Schmidt, Christina; Escobar Wolf, Kaibil; Lins, Lidia; Martínez Arbizu, Pedro; Brandt, Angelika

2018-02-01

Despite the increasing sampling effort that occurred in the deep-sea environment during the last decades, knowledge about meiofauna ecology in trenches and Fracture Zones is still scarce. Based on the lack of this information, a longitudinal transect across the Vema Fracture Zone in the North Atlantic was sampled to test whether meiofauna abundances differ between Northeast and Northwest Atlantic basins, separated by the Mid-Atlantic Ridge. Also, for examination of meiofauna depth pattern, the Puerto Rico trench floor, its upper trench slope and the Western North Atlantic abyssal were investigated. In this study, meiofauna communities were dominated by Nematoda (93%) and Copepoda (4%). The highest total abundance of meiofauna was found in the Puerto Rico trench and the lowest in the Western basin. We found significant differences between the Eastern and Western Atlantic basins, which were potentially caused by differences in current regimes. Stronger currents observed in the Western basin possibly led to the coarser sediment grain size observed in this region, and consequently to the lower abundances of the major groups found there. Besides grain size, the total abundance of meiofauna was significantly correlated with total nitrogen, total organic carbon, and water depth. Moreover, our study reveals a trend of increasing abundance of total meiofauna with increasing water depth in the Puerto Rico trench. Also, significant differences between the Western abyssal and the Puerto Rico trench were discovered. Generally, the meiofauna abundance in the investigated area decreased from East to West but increased with increasing water depth in the Puerto Rico trench. Due to funnelling of organic sediments increased food availability towards deeper regions in trenches could occur and promote higher abundance.

Decadal changes in North Atlantic atmospheric circulation patterns recorded by sand spits since 1800 CE

NASA Astrophysics Data System (ADS)

Poirier, Clément; Tessier, Bernadette; Chaumillon, Éric; Bertin, Xavier; Fruergaard, Mikkel; Mouazé, Dominique; Noël, Suzanne; Weill, Pierre; Wöppelmann, Guy

2017-03-01

Present-day coastal barriers represent around 15% of the world's oceanic shorelines, and play an important role as early warning indicators of environmental change. Among them, wave-dominated barriers are dynamic landforms that tend to migrate landward in response to storms and sea-level change. High rates of sediment supply can locally offset the global retrogradation trend, providing valuable records of past environmental change occurring on transgressive coasts. However, geochronological control limits the temporal resolution of such records to millennial or centennial timescales, and the decadal or even faster response of wave-built barriers to historical climate changes is therefore poorly understood. In this study, we show that shoreline dynamics of sand spits reconstructed from old cartographic documents has been synchronous on both margins of the North Atlantic Ocean since about 1800 CE. Spit growth accelerated drastically during three periods lasting about 15 years, characterised by positive North Atlantic Oscillation (NAO) and negative East Atlantic-West Russia (EA-WR) atmospheric circulation patterns. These changes are in phase with periods of increased volcanic activity. We use a high-resolution wave hindcast (1948-2014 CE) in a reference area to confirm the association between NAO and EA-WR as a proxy for offshore and nearshore wave height and for associated longshore sediment transport (LST) involved in spit growth. A 24-month lagged correlation between sediment transport and volcanic aerosol optical thickness (concentration of ashes in the atmosphere) is observed, suggesting that spit shoreline dynamics at the decadal timescale is partially forced by external climate drivers via cascading effects on atmospheric circulation patterns and wave climate. Our results imply that NAO variability alone is not sufficient to understand the evolution of wave-built coastal environments. The associated sediment record can be used to reconstruct multi-decadal variability of other climate patterns.

Statistical downscaling forecast of Chinese winter temperature based on the autumn SST anomalies

NASA Astrophysics Data System (ADS)

Lu, J.

2017-12-01

This study investigates the impacts of the autumn sea surface temperature anomalies (SSTA) on interannual variations of Chinese winter temperature, and discusses the potential predictability of December-January-February (DJF) 2-m air temperature anomalies (TSA) over China based on the intimate linkage between the DJF TSA and autumn SSTA. According to the Empirical Orthogonal Function (EOF) analysis, three leading EOF modes jointly account for 80% of the total TSA variances and are characterized by a homogeneous spatial pattern, a north-south seesaw and a cross structure. The first three EOFs exhibit a stable feature revealed by cross-validation, suggesting the potential predictability of the DJF TSA. The EOF1 mode is influenced by changes in the intensities of the Siberian High (SH), East Asian winter monsoon (EAWM) and East Asian Trough related to an Eurasian pattern teleconnection, which can be tracked back to September-October-November (SON) SSTA associated with two SSTA tripole patterns in the North Pacific and North Atlantic, a dipole mode in the Indian Ocean and an ENSO-like mode in the equatorial and subtropical Pacific. However, the Arctic Oscillation plays an important role in the second mode. The teleconnection connecting the atmospheric circulation anomalies in two hemispheres indicates that the configuration of global SON SSTA induces the two annular modes and causes a TSA oscillation between the northern and southern parts of China. The third mode is related to the westward shift of the SH and western pathway EAWM, which are attributed to two dipole modes in the North Pacific and South Pacific, Atlantic Multidecadal Oscillation and Indian Ocean Basin Mode. Therefore a physically-based statistical model is established based on autumn SSTA indices. Cross-validation suggests that this statistical downscaling forecast model shows a good performance in predicting the DJF TSA.

Links between large-scale circulation patterns and streamflow in Central Europe: A review

NASA Astrophysics Data System (ADS)

Steirou, Eva; Gerlitz, Lars; Apel, Heiko; Merz, Bruno

2017-06-01

We disentangle the relationships between streamflow and large-scale atmospheric circulation in Central Europe (CE), an area affected by climatic influences from different origins (Atlantic, Mediterranean and Continental) and characterized by diverse topography and flow regimes. Our literature review examines in detail the links between mean, high and low flows in CE and large-scale circulation patterns, with focus on two closely related phenomena, the North Atlantic Oscillation (NAO) and the Western-zonal circulation (WC). For both patterns, significant relations, consistent between different studies, are found for large parts of CE. The strongest links are found for the winter season, forming a dipole-like pattern with positive relationships with streamflow north of the Alps and the Carpathians for both indices and negative relationships for the NAO in the south. An influence of winter NAO is also detected in the amplitude and timing of snowmelt flows later in the year. Discharge in CE has further been linked to other large-scale climatic modes such as the Scandinavia pattern (SCA), the East Atlantic/West Russian pattern (EA/WR), the El Niño-Southern Oscillation (ENSO) and synoptic weather patterns such as the Vb weather regime. Different mechanisms suggested in the literature to modulate links between streamflow and the NAO are combined with topographical characteristics of the target area in order to explain the divergent NAO/WC influence on streamflow in different parts of CE. In particular, a precipitation mechanism seems to regulate winter flows in North-Western Germany, an area with short duration of snow cover and with rainfall-generated floods. The precipitation mechanism is also likely in Southern CE, where correlations between the NAO and temperature are low. Finally, in the rest of the study area (Northern CE, Alpine region), a joint precipitation-snow mechanism influences floods not only in winter, but also in the spring/snowmelt period, providing some possibilities for flood forecasting.

The North Atlantic Ocean as habitat for Calanus finmarchicus: Environmental factors and life history traits

NASA Astrophysics Data System (ADS)

Melle, Webjørn; Runge, Jeffrey; Head, Erica; Plourde, Stéphane; Castellani, Claudia; Licandro, Priscilla; Pierson, James; Jonasdottir, Sigrun; Johnson, Catherine; Broms, Cecilie; Debes, Høgni; Falkenhaug, Tone; Gaard, Eilif; Gislason, Astthor; Heath, Michael; Niehoff, Barbara; Nielsen, Torkel Gissel; Pepin, Pierre; Stenevik, Erling Kaare; Chust, Guillem

2014-12-01

Here we present a new, pan-Atlantic compilation and analysis of data on Calanus finmarchicus abundance, demography, dormancy, egg production and mortality in relation to basin-scale patterns of temperature, phytoplankton biomass, circulation and other environmental characteristics in the context of understanding factors determining the distribution and abundance of C. finmarchicus across its North Atlantic habitat. A number of themes emerge: (1) the south-to-north transport of plankton in the northeast Atlantic contrasts with north-to-south transport in the western North Atlantic, which has implications for understanding population responses of C. finmarchicus to climate forcing, (2) recruitment to the youngest copepodite stages occurs during or just after the phytoplankton bloom in the east whereas it occurs after the bloom at many western sites, with up to 3.5 months difference in recruitment timing, (3) the deep basin and gyre of the southern Norwegian Sea is the centre of production and overwintering of C. finmarchicus, upon which the surrounding waters depend, whereas, in the Labrador/Irminger Seas production mainly occurs along the margins, such that the deep basins serve as collection areas and refugia for the overwintering populations, rather than as centres of production, (4) the western North Atlantic marginal seas have an important role in sustaining high C. finmarchicus abundance on the nearby coastal shelves, (5) differences in mean temperature and chlorophyll concentration between the western and eastern North Atlantic are reflected in regional differences in female body size and egg production, (6) regional differences in functional responses of egg production rate may reflect genetic differences between western and eastern populations, (7) dormancy duration is generally shorter in the deep waters adjacent to the lower latitude western North Atlantic shelves than in the east, (8) there are differences in stage-specific daily mortality rates between eastern and western shelves and basins, but the survival trajectories for cohort development from CI to CV are similar, and (9) early life stage survival is much lower in regions where C. finmarchicus is found with its congeners, C. glacialis and/or C. hyperboreus. This compilation and analysis provides new knowledge for evaluation and parameterisation of population models of C. finmarchicus and their responses to climate change in the North Atlantic. The strengths and weaknesses of modeling approaches, including a statistical approach based on ecological niche theory and a dynamical approach based on knowledge of spatial population dynamics and life history, are discussed, as well as needs for further research.

The effect of the East Atlantic pattern on the precipitation δ18O-NAO relationship in Europe

NASA Astrophysics Data System (ADS)

Comas-Bru, L.; McDermott, F.; Werner, M.

2016-10-01

The North Atlantic Oscillation (NAO) is known to influence precipitation δ18O (δ18Op) through its control on air temperature and on the trajectory of the westerly winds that carry moisture onto Europe during boreal winters. Hence, paleoclimate studies seeking to reconstruct the NAO can exploit the δ18O signal that is commonly preserved in natural archives such as stalagmites, ice cores, tree rings and lake sediments. However, such reconstructions should consider the uncertainties that arise from non-stationarities in the δ18Op-NAO relationship. Here, new insights into the causes of these temporal non-stationarities are presented for the European region using both observations (GNIP database) and the output of an isotope-enabled general circulation model (ECHAM5-wiso). The results show that, although the East Atlantic (EA) pattern is generally uncorrelated to δ18Op during the instrumental period, its polarity affects the δ18Op-NAO relationship. Non-stationarities in this relationship result from spatial shifts of the δ18Op-NAO correlated areas as a consequence of different NAO/EA combinations. These shifts are consistent with those reported previously for NAO-winter climate variables and the resulting non-stationarities mean that δ18O-based NAO reconstructions could be compromised if the balance of positive and negative NAO/EA states differs substantially in a calibration period compared with the period of interest in the past. The same approach has been followed to assess the relationships between δ18Op and both winter total precipitation and winter mean surface air temperature, with similar results. Crucially, this study also identifies regions within Europe where temporal changes in the NAO, air temperature and precipitation can be more robustly reconstructed using δ18O time series from natural archives, irrespective of concomitant changes in the EA.

Atmospheric teleconnection influence on North American land surface phenology

NASA Astrophysics Data System (ADS)

Dannenberg, Matthew P.; Wise, Erika K.; Janko, Mark; Hwang, Taehee; Kolby Smith, W.

2018-03-01

Short-term forecasts of vegetation activity are currently not well constrained due largely to our lack of understanding of coupled climate-vegetation dynamics mediated by complex interactions between atmospheric teleconnection patterns. Using ecoregion-scale estimates of North American vegetation activity inferred from remote sensing (1982-2015), we examined seasonal and spatial relationships between land surface phenology and the atmospheric components of five teleconnection patterns over the tropical Pacific, north Pacific, and north Atlantic. Using a set of regression experiments, we also tested for interactions among these teleconnection patterns and assessed predictability of vegetation activity solely based on knowledge of atmospheric teleconnection indices. Autumn-to-winter composites of the Southern Oscillation Index (SOI) were strongly correlated with start of growing season timing, especially in the Pacific Northwest. The two leading modes of north Pacific variability (the Pacific-North American, PNA, and West Pacific patterns) were significantly correlated with start of growing season timing across much of southern Canada and the upper Great Lakes. Regression models based on these Pacific teleconnections were skillful predictors of spring phenology across an east-west swath of temperate and boreal North America, between 40°N-60°N. While the North Atlantic Oscillation (NAO) was not strongly correlated with start of growing season timing on its own, we found compelling evidence of widespread NAO-SOI and NAO-PNA interaction effects. These results suggest that knowledge of atmospheric conditions over the Pacific and Atlantic Oceans increases the predictability of North American spring phenology. A more robust consideration of the complexity of the atmospheric circulation system, including interactions across multiple ocean basins, is an important step towards accurate forecasts of vegetation activity.

Subpolar Atlantic cooling and North American east coast warming linked to AMOC slowdown

NASA Astrophysics Data System (ADS)

Rahmstorf, Stefan; Caesar, Levke; Feulner, Georg; Saba, Vincent

2017-04-01

Reconstructing the history of the Atlantic Meridional Overturning Circulation (AMOC) is difficult due to the limited availability of data. One approach has been to use instrumental and proxy data for sea surface temperature (SST), taking multi-decadal and longer SST variations in the subpolar gyre region as indicator for AMOC changes [Rahmstorf et al., 2015]. Recent high-resolution global climate model results [Saba et al., 2016] as well as dynamical theory and conceptual modelling [Zhang and Vallis, 2007] suggest that an AMOC weakening will not only cool the subpolar Atlantic but simultaneously warm the Northwest Atlantic between Cape Hatteras and Nova Scotia, thus providing a characteristic SST pattern associated with AMOC variations. We analyse sea surface temperature (SST) observations from this region together with high-resolution climate model simulations to better understand the linkages of SST variations to AMOC variability and to provide further evidence for an ongoing AMOC slowdown. References Rahmstorf, S., J. E. Box, G. Feulner, M. E. Mann, A. Robinson, S. Rutherford, and E. J. Schaffernicht (2015), Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation, Nature Climate Change, 5(5), 475-480, doi: 10.1038/nclimate2554. Saba, V. S., et al. (2016), Enhanced warming of the Northwest Atlantic Ocean under climate change, Journal of Geophysical Research-Oceans, 121(1), 118-132, doi: 10.1002/2015JC011346. Zhang, R., and G. K. Vallis (2007), The Role of Bottom Vortex Stretching on the Path of the North Atlantic Western Boundary Current and on the Northern Recirculation Gyre, Journal of Physical Oceanography, 37(8), 2053-2080, doi: 10.1175/jpo3102.1.

6. Historic American Buildings Survey Arthur C. Haskell, Photographer. 1935 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Historic American Buildings Survey Arthur C. Haskell, Photographer. 1935 (b) Ext-View of remaining East Portion from Atlantic Ave. - India Wharf Stores, 306-308 Atlantic Avenue, Boston, Suffolk County, MA

Characteristics of storms driving wave-induced seafloor mobility on the U.S. East Coast continental shelf

USGS Publications Warehouse

Dalyander, P. Soupy; Butman, Bradford

2015-01-01

This study investigates the relationship between spatial and temporal patterns of wave-driven sediment mobility events on the U.S. East Coast continental shelf and the characteristics of the storms responsible for them. Mobility events, defined as seafloor wave stress exceedance of the critical stress of 0.35 mm diameter sand (0.2160 Pa) for 12 or more hours, were identified from surface wave observations at National Data Buoy Center buoys in the Middle Atlantic Bight (MAB) and South Atlantic Bight (SAB) over the period of 1997-2007. In water depths ranging from 36-48 m, there were 4-9 mobility events/year of 1-2 days duration. Integrated wave stress during events (IWAVES) was used as a combined metric of wave-driven mobility intensity and duration. In the MAB, over 67% of IWAVES was caused by extratropical storms, while in the SAB, greater than 66% of IWAVES was caused by tropical storms. On average, mobility events were caused by waves generated by storms located 800+ km away. Far-field hurricanes generated swell 2-4 days before the waves caused mobility on the shelf. Throughout most of the SAB, mobility events were driven by storms to the south, east, and west. In the MAB and near Cape Hatteras, winds from more northerly storms and low-pressure extratropical systems in the mid-western U.S. also drove mobility events. Waves generated by storms off the SAB generated mobility events along the entire U.S. East Coast shelf north to Cape Cod, while Cape Hatteras shielded the SAB area from swell originating to the north offshore of the MAB.

A seesaw in Mediterranean precipitation during the Roman Period linked to millennial-scale changes in the North Atlantic

NASA Astrophysics Data System (ADS)

Dermody, B. J.; de Boer, H. J.; Bierkens, M. F. P.; Weber, S. L.; Wassen, M. J.; Dekker, S. C.

2012-03-01

We present a reconstruction of the change in climatic humidity around the Mediterranean between 3000-1000 yr BP. Using a range of proxy archives and model simulations we demonstrate that climate during this period was typified by a millennial-scale seesaw in climatic humidity between Spain and Israel on one side and the Central Mediterranean and Turkey on the other, similar to precipitation anomalies associated with the East Atlantic/West Russia pattern in current climate. We find that changes in the position and intensity of the jet stream indicated by our analysis correlate with millennial changes in North Atlantic sea surface temperature. A model simulation indicates the proxies of climatic humidity used in our analysis were unlikely to be influenced by climatic aridification caused by deforestation during the Roman Period. That finding is supported by an analysis of the distribution of archaeological sites in the Eastern Mediterranean which exhibits no evidence that human habitation distribution changed since ancient times as a result of climatic aridification. Therefore we conclude that changes in climatic humidity over the Mediterranean during the Roman Period were primarily caused by a modification of the jet stream linked to sea surface temperature change in the North Atlantic. Based on our findings, we propose that ocean-atmosphere coupling may have contributed to regulating Atlantic Meridional Overturning Circulation intensity during the period of analysis.

Observed linkages between the northern annular mode/North Atlantic Oscillation, cloud incidence, and cloud radiative forcing

NASA Astrophysics Data System (ADS)

Li, Ying; Thompson, David W. J.; Huang, Yi; Zhang, Minghong

2014-03-01

The signature of the northern annular mode/North Atlantic Oscillation (NAM/NAO) in the vertical and horizontal distribution of tropospheric cloudiness is investigated in CloudSat and CALIPSO data from June 2006 to April 2011. During the Northern Hemisphere winter, the positive polarity of the NAM/NAO is marked by increases in zonally averaged cloud incidence north of ~60°N, decreases between ~25 and 50°N, and increases in the subtropics. The tripolar-like anomalies in cloud incidence associated with the NAM/NAO are largest over the North Atlantic Ocean basin/Middle East and are physically consistent with the NAM/NAO-related anomalies in vertical motion. Importantly, the NAM/NAO-related anomalies in tropospheric cloud incidence lead to significant top of atmosphere cloud radiative forcing anomalies that are comparable in amplitude to those associated with the NAM/NAO-related temperature anomalies. The results provide observational evidence that the most prominent pattern of Northern Hemisphere climate variability is significantly linked to variations in cloud radiative forcing. Implications for two-way feedback between extratropical dynamics and cloud radiative forcing are discussed.

High Fidelity VSF Measurements and Inversion for RaDyO (Hi Fi RaDyO)

DTIC Science & Technology

2007-09-30

0.025 um size; this time with all WLE ECO BB sensors as well. ployment in Hawaii (SORTIE) 21-28: Deployment in northwest Atlantic (OCVAL: Endeavor...between phytoplankton pigment composition and in situ spectral absorption measurements in East Sound, Orcas , Island, WA. Limnol. Oceanogr., 48:632-646...concentration and optical properties of surface waters in the South East Pacific and Atlantic Oceans. Biogeosciences, in review. Twardowski, M.S., H

A molecular comparison of Alaskan and North East Atlantic Halicondria panicea (Pallas 1766) (Porifera: Demospongiae)

USGS Publications Warehouse

Erpenbeck, Dirk; Knowlton, Anne L.; Talbot, Sandra L.; Highsmith, Ray C.; van Soest, Rob W.M.

2004-01-01

The intraspecific relationships between populations of Alaskan Halichondria cf. panicea are the subjects of ongoing research. In this study we compare CO1 sequences of Alaskan Halichondria cf. panicea with North East Atlantic Halichondria panicea and its sister species Halichondria bowerbanki. Alaskan Halichondria cf. panicea form a well-supported sister group to the European Halichondria panicea/ H. bowerbanki species complex in the resulting gene tree and cluster distantly from their European conspecifics.

Spatial coherence and large-scale drivers of drought

NASA Astrophysics Data System (ADS)

Svensson, Cecilia; Hannaford, Jamie

2017-04-01

Drought is a potentially widespread and generally multifaceted natural phenomenon affecting all aspects of the hydrological cycle. It mainly manifests itself at seasonal, or longer, time scales. Here, we use seasonal river flows across the climatologically and topographically diverse UK to investigate the spatial coherence of drought, and explore its oceanic and atmospheric drivers. A better understanding of the spatial characteristics and drivers will improve forecasting and help increase drought preparedness. The location of the UK in the mid-latitude belt of predominantly westerly winds, together with a pronounced topographical divide running roughly from north to south, produce strong windward and leeward effects. Weather fronts associated with storms tracking north-eastward between Scotland and Iceland typically lead to abundant precipitation in the mountainous north and west, while the south and east remain drier. In contrast, prolonged precipitation in eastern Britain tends to be associated with storms on a more southerly track, producing precipitation in onshore winds on the northern side of depressions. Persistence in the preferred storm tracks can therefore result in periods of wet/dry conditions across two main regions of the UK, a mountainous northwest region exposed to westerly winds and a more sheltered, lowland southeast region. This is reflected in cluster analyses of monthly river flow anomalies. A further division into three clusters separates out a region of highly permeable, slowly responding, catchments in the southeast. An expectation that the preferred storm tracks over seasonal time scales can be captured by atmospheric airflow indices, which in turn may be related to oceanic conditions, suggests that statistical methods may be used to describe the relationships between UK regional streamflows, and oceanic and atmospheric drivers. Such relationships may be concurrent or lagged, and the longer response time of the group of permeable catchments in the southeast also introduces lags in the statistical relationships. Three-month aggregations of the data were used to investigate potential oceanic and atmospheric drivers of streamflow drought in the three UK regions. Significant concurrent relationships were found for different parts of the year for several indices of northern hemisphere airflow patterns, including the North Atlantic Oscillation, the Arctic Oscillation, the East Atlantic, the East Atlantic/West Russia, and the Scandinavia patterns. Significant relationships with oceanic and atmospheric indices representing the El Niño/Southern Oscillation were found for both concurrent and lagged analyses.

State dependence of climatic instability over the past 720,000 years from Antarctic ice cores and climate modeling.

PubMed

Kawamura, Kenji; Abe-Ouchi, Ayako; Motoyama, Hideaki; Ageta, Yutaka; Aoki, Shuji; Azuma, Nobuhiko; Fujii, Yoshiyuki; Fujita, Koji; Fujita, Shuji; Fukui, Kotaro; Furukawa, Teruo; Furusaki, Atsushi; Goto-Azuma, Kumiko; Greve, Ralf; Hirabayashi, Motohiro; Hondoh, Takeo; Hori, Akira; Horikawa, Shinichiro; Horiuchi, Kazuho; Igarashi, Makoto; Iizuka, Yoshinori; Kameda, Takao; Kanda, Hiroshi; Kohno, Mika; Kuramoto, Takayuki; Matsushi, Yuki; Miyahara, Morihiro; Miyake, Takayuki; Miyamoto, Atsushi; Nagashima, Yasuo; Nakayama, Yoshiki; Nakazawa, Takakiyo; Nakazawa, Fumio; Nishio, Fumihiko; Obinata, Ichio; Ohgaito, Rumi; Oka, Akira; Okuno, Jun'ichi; Okuyama, Junichi; Oyabu, Ikumi; Parrenin, Frédéric; Pattyn, Frank; Saito, Fuyuki; Saito, Takashi; Saito, Takeshi; Sakurai, Toshimitsu; Sasa, Kimikazu; Seddik, Hakime; Shibata, Yasuyuki; Shinbori, Kunio; Suzuki, Keisuke; Suzuki, Toshitaka; Takahashi, Akiyoshi; Takahashi, Kunio; Takahashi, Shuhei; Takata, Morimasa; Tanaka, Yoichi; Uemura, Ryu; Watanabe, Genta; Watanabe, Okitsugu; Yamasaki, Tetsuhide; Yokoyama, Kotaro; Yoshimori, Masakazu; Yoshimoto, Takayasu

2017-02-01

Climatic variabilities on millennial and longer time scales with a bipolar seesaw pattern have been documented in paleoclimatic records, but their frequencies, relationships with mean climatic state, and mechanisms remain unclear. Understanding the processes and sensitivities that underlie these changes will underpin better understanding of the climate system and projections of its future change. We investigate the long-term characteristics of climatic variability using a new ice-core record from Dome Fuji, East Antarctica, combined with an existing long record from the Dome C ice core. Antarctic warming events over the past 720,000 years are most frequent when the Antarctic temperature is slightly below average on orbital time scales, equivalent to an intermediate climate during glacial periods, whereas interglacial and fully glaciated climates are unfavourable for a millennial-scale bipolar seesaw. Numerical experiments using a fully coupled atmosphere-ocean general circulation model with freshwater hosing in the northern North Atlantic showed that climate becomes most unstable in intermediate glacial conditions associated with large changes in sea ice and the Atlantic Meridional Overturning Circulation. Model sensitivity experiments suggest that the prerequisite for the most frequent climate instability with bipolar seesaw pattern during the late Pleistocene era is associated with reduced atmospheric CO 2 concentration via global cooling and sea ice formation in the North Atlantic, in addition to extended Northern Hemisphere ice sheets.

State dependence of climatic instability over the past 720,000 years from Antarctic ice cores and climate modeling

PubMed Central

Kawamura, Kenji; Abe-Ouchi, Ayako; Motoyama, Hideaki; Ageta, Yutaka; Aoki, Shuji; Azuma, Nobuhiko; Fujii, Yoshiyuki; Fujita, Koji; Fujita, Shuji; Fukui, Kotaro; Furukawa, Teruo; Furusaki, Atsushi; Goto-Azuma, Kumiko; Greve, Ralf; Hirabayashi, Motohiro; Hondoh, Takeo; Hori, Akira; Horikawa, Shinichiro; Horiuchi, Kazuho; Igarashi, Makoto; Iizuka, Yoshinori; Kameda, Takao; Kanda, Hiroshi; Kohno, Mika; Kuramoto, Takayuki; Matsushi, Yuki; Miyahara, Morihiro; Miyake, Takayuki; Miyamoto, Atsushi; Nagashima, Yasuo; Nakayama, Yoshiki; Nakazawa, Takakiyo; Nakazawa, Fumio; Nishio, Fumihiko; Obinata, Ichio; Ohgaito, Rumi; Oka, Akira; Okuno, Jun’ichi; Okuyama, Junichi; Oyabu, Ikumi; Parrenin, Frédéric; Pattyn, Frank; Saito, Fuyuki; Saito, Takashi; Saito, Takeshi; Sakurai, Toshimitsu; Sasa, Kimikazu; Seddik, Hakime; Shibata, Yasuyuki; Shinbori, Kunio; Suzuki, Keisuke; Suzuki, Toshitaka; Takahashi, Akiyoshi; Takahashi, Kunio; Takahashi, Shuhei; Takata, Morimasa; Tanaka, Yoichi; Uemura, Ryu; Watanabe, Genta; Watanabe, Okitsugu; Yamasaki, Tetsuhide; Yokoyama, Kotaro; Yoshimori, Masakazu; Yoshimoto, Takayasu

2017-01-01

Climatic variabilities on millennial and longer time scales with a bipolar seesaw pattern have been documented in paleoclimatic records, but their frequencies, relationships with mean climatic state, and mechanisms remain unclear. Understanding the processes and sensitivities that underlie these changes will underpin better understanding of the climate system and projections of its future change. We investigate the long-term characteristics of climatic variability using a new ice-core record from Dome Fuji, East Antarctica, combined with an existing long record from the Dome C ice core. Antarctic warming events over the past 720,000 years are most frequent when the Antarctic temperature is slightly below average on orbital time scales, equivalent to an intermediate climate during glacial periods, whereas interglacial and fully glaciated climates are unfavourable for a millennial-scale bipolar seesaw. Numerical experiments using a fully coupled atmosphere-ocean general circulation model with freshwater hosing in the northern North Atlantic showed that climate becomes most unstable in intermediate glacial conditions associated with large changes in sea ice and the Atlantic Meridional Overturning Circulation. Model sensitivity experiments suggest that the prerequisite for the most frequent climate instability with bipolar seesaw pattern during the late Pleistocene era is associated with reduced atmospheric CO2 concentration via global cooling and sea ice formation in the North Atlantic, in addition to extended Northern Hemisphere ice sheets. PMID:28246631

Towards the prediction of the East Africa short rains based on sea-surface temperature-atmosphere coupling

NASA Astrophysics Data System (ADS)

Mutai, C. C.; Ward, M. N.; Colman, A. W.

1998-07-01

It is shown that the July-September sea-surface temperature (SST) pattern contains moderately strong relationships with the October-December (OND) seasonal rainfall total averaged across East Africa 15°S-5°N, 30°-41.25°E. The relations can be described by using three rotated global SST empirical orthogonal functions (EOFs), mainly measuring aspects of SST patterns in the tropical Pacific (related to El Niño/Southern Oscillation), tropical Indian and, to a lesser extent, tropical Atlantic. Confidence in the relationships is raised because the three EOFs correlate significantly with OND near-surface divergence over the tropical Pacific, Indian and Atlantic Oceans (extending into Northern mid-latitudes), as well as with the rainfall in East Africa and also with rainfall across southern and western tropical Africa.For the East African region, multiple linear regression (MLR) and linear discriminant analysis prediction models are tested. The predictors are pre-rainfall season values of the three rotated SST EOFs. The predictors use information through September. Validating MLR hindcasts using a 1945-1966 (1967-1988) training period and a 1967-1988 (1945-1966) testing period between 30 to 60% of the area-averaged rainfall variance is explained. To achieve unbiased estimates of the expected skill of a forecast system, it is safest to keep model training and testing periods completely separate. The above strategy achieves this in the most important step of ensuring that the models fit the SST predictors to the rainfall predictand using years independent of the testing period. However, the EOFs were calculated over 1901-1980, so for hindcasts prior to 1981, the EOFs describe the SST variability a little better than could be achieved in real-time, which could inflate skill estimates. Tests in the years 1981-1994, independent of the 1901-1980 eigenvector analysis period, do produce similar levels of skill, but a few more forecast years are needed to confirm this result. It is shown that the mean verification at each individual location within East Africa is somewhat lower, which is important to consider for some applications. The need to monitor the prediction relationships and update the models is emphasised. Furthermore, these forecasts only become available as the OND season is underway, though some evidence is found for one of the EOF predictors having skill as early as June.

The Cenozoic Cooling - continental signals from the Atlantic and Pacific side of Eurasia

NASA Astrophysics Data System (ADS)

Utescher, Torsten; Bondarenko, Olesya V.; Mosbrugger, Volker

2015-04-01

The evolution of Cenozoic continental climate signals from the Atlantic and Pacific side of Eurasia can be assessed for the first time by comparing climate records obtained for two mid-latitudinal regions. For the West, a detailed climate record over the past 45 Ma, based on palaeofloras from two Northern German Cenozoic basins (Mosbrugger et al., 2005) revealed major trends and shorter-term events throughout the Cenozoic Cooling, thus testifying the close correlation of continental and marine temperature evolution as derived from oxygen isotopes (Zachos et al., 2008). Using the same methodology, we analyze a total of 14 floral horizons originating from continental strata of Southern Primory'e (Russia) in order to study the evolution at the eastern side of the continent. The Primory'e record spans the middle Eocene to early Pleistocene. As the coeval record for the Atlantic side, it reflects major global signals of Cenozoic climate change such as the temperature decline throughout the late Eocene, coinciding with the growth of Antarctic Ice-sheets, warming during the Mid-Miocene Climatic Optimum, and step-wise cooling throughout the later Neogene. The comparison of both records reveals differing regional patterns. The considerable longitudinal temperature gradient, currently existing between both study areas, already began to evolve during the Aquitanian, and was very significant during the Mid-Miocene Climatic Optimum. The temperature offset between East and West is likely attributable to an effective North Atlantic Current, already operational from the late early Miocene onwards bringing about mild winters and low seasonality in Western Europe, while in Primory'e, seasonality steadily increased from the late Oligocene on. The strong late Pliocene decline of cold month mean temperatures recorded in Primory'e is supposed to coincide with the establishment of the Siberian High as semi-permanent structure of the Northern Hemisphere circulation pattern. When comparing the precipitation records obtained for both study areas, an unexpected co-variability at the longer-term (in the order of 5-20 Ma) is noted, pointing to continent-wide hydrological changes. The steady decline of mean annual precipitation in the Primory'e record, beginning in the Bartonian and culminating in the Aquitanian, coincides with an aridity increase reported from coeval Chinese inland localities of the mid-latitudes. The seasonality patterns of rainfall point to progressive intensification of the East Asian Summer Monsoon in Primory'e since the later Tortonian while the post-Zanclean decline of the precipitation of the dry season can be related to an increasing impact of the winter monsoon.

Transport of Antarctic Bottom Water through passages in the East Azores Ridge (37° N) in the East Atlantic

NASA Astrophysics Data System (ADS)

Tarakanov, R. Yu.; Morozov, E. G.; Gritsenko, A. M.; Demidova, T. A.; Makarenko, N. I.

2013-07-01

The structure of northerly overflow of Antarctic Bottom Water (AABW) through passages in the East Azores Ridge (37° N) in the East Atlantic from the Madeira Basin to the Iberian Basin is studied on the basis of hydrographic measurements carried out by the Institute of Oceanology, Russian Academy of Sciences (RAS) in October 2011, historical World Ocean Data Base 2009, and recent data on the bottom topography. The overflow of the coldest layers of this water occurs through two passages with close depths at 16° W (Discovery Gap) and at 19°30' W (nameless Western Gap). It is shown that it is likely that the role of the latter passage in water transport was underestimated in earlier publications because the water (2.01°C) found in the region north of the Western Gap was cooler than in the region north of the Discovery Gap (2.03°C). In 2011, we found a decrease of 0.01°C in the AABW temperature near the bottom compared to previous measurements in 1982 (from 2.011°C to 2.002°C). Analysis of the historical database shows that this decrease is most likely caused by the cooling trend in the abyssal waters in the East Atlantic basins.

Impacts of radiation management techniques on the North Atlantic Oscillation

NASA Astrophysics Data System (ADS)

Adakudlu, Muralidhar; Helge Otterå, Odd; Tjiputra, Jerry; Muri, Helene; Grini, Alf; Schulz, Michael

2017-04-01

The effectiveness of various climate engineering techniques in limiting the global warming signal to reasonable levels has been the topic of state-of-the-art research on climate change. Using an Earth system model, we show that these techniques have the potential to bring down the high CO2 concentration climate in RCP8.5 to a moderate climate similar to RCP4.5 in terms of global temperature. Nevertheless, their influence on the regional aspects of atmospheric circulation is not clear. The regional circulation patterns in the atmosphere are largely characterized by the natural variability modes, such as the North Atlantic Oscillation (NAO). In this study, we assess the impacts of three radiation managment techniques, namely, Stratospheric Aerosol Injection (SAI), Marine Sky Brightening (MSB) and Cirrus Cloud Thinning (CCT), on the structure and features of the NAO. The results indicate an east-northeastward shift as well as intensification of the NAO spatial pattern in the global warming scenarios of RCP4.5 and RCP8.5, with the signal being most intense in the latter. The climate engineering forcings when applied to the RCP8.5 case tend to reduce the strength of the NAO with little impact on its position. The CCT case appears to have the maximum effect on the NAO signal. The patterns of cloud radiative forcing, expressed as the difference between net radiative forcing at TOA under average conditions and clear sky conditions, reveal a northeastward shift of the radiative heating in the north Atlantic region. This implies a possible link between the changes in the NAO signal and the cloud radiative forcing.

77 FR 50019 - Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

... 1625-AA00 Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL AGENCY: Coast Guard, DHS... waters of the Atlantic Ocean located east of Cocoa Beach, Florida during the Cocoa Beach Air Show. The Cocoa Beach Air Show will include aircraft engaging in aerobatic maneuvers. The event is scheduled to...

Numerical simulation on the southern flood and northern drought in summer 2014 over Eastern China

NASA Astrophysics Data System (ADS)

Xu, Lianlian; He, Shengping; Li, Fei; Ma, Jiehua; Wang, Huijun

2017-12-01

In summer 2014, Eastern China suffered a typical "southern flood and northern drought" anomalous climate. Observational analyses indicated that the anomalous vertical motion, East Asian subtropical westerly jet stream, and the East Asian summer monsoon (EASM) played important roles in the formation of such precipitation anomaly. Furthermore, using the climate model (IAP-AGCM-4.1) perturbed by simultaneous observed sea surface temperature anomalies (SSTAs) in global scale and four different regions (North Pacific, Indian Ocean, North Atlantic, and Equatorial Pacific), this study investigated the potential contribution of ocean to such "southern flood and northern drought" over Eastern China in summer 2014. The simulations forced by global-scale SSTAs or North Pacific SSTAs displayed the most similarity to the observed "southern flood and northern drought" over Eastern China. It was revealed that the global-scale and North Pacific SSTAs influenced the rainfall over Eastern China via modulating the EASM. The related simulations successfully reproduced the associated atmospheric circulation anomalies. The experiment driven by Indian Ocean SSTAs could also reproduce the similar precipitation anomaly pattern and suggested that the Indian Ocean exerted pronounced influence on the North Pacific Subtropical High. Additionally, the simulations forced by SSTAs in the North Atlantic and Equatorial Pacific successfully reproduced the northern drought but failed to capture the southern flood. The simulations suggested that precipitation anomaly over Eastern China in summer 2014 was a comprehensive effect of global SSTAs and the dominant contribution to the "southern flood and northern drought" pattern came from the North Pacific and Indian Ocean.

First records of Hippocampus algiricus in the Canary Islands (north-east Atlantic Ocean) with an observation of hybridization with Hippocampus hippocampus.

PubMed

Otero-Ferrer, F; Herrera, R; López, A; Socorro, J; Molina, L; Bouza, C

2015-10-01

Morphometric and genetic analyses confirmed the first records of the West African seahorse Hippocampus algiricus at Gran Canaria Island (north-east Atlantic Ocean), and also the first evidence of interspecific hybridization in seahorses. These results provide additional data on the distribution of H. algiricus that may help to establish future conservation strategies, and uncover a new potential sympatric scenario between H. algiricus and Hippocampus hippocampus. © 2015 The Fisheries Society of the British Isles.

Sensitivity of marine protected area network connectivity to atmospheric variability

NASA Astrophysics Data System (ADS)

Fox, Alan D.; Henry, Lea-Anne; Corne, David W.; Roberts, J. Murray

2016-11-01

International efforts are underway to establish well-connected systems of marine protected areas (MPAs) covering at least 10% of the ocean by 2020. But the nature and dynamics of ocean ecosystem connectivity are poorly understood, with unresolved effects of climate variability. We used 40-year runs of a particle tracking model to examine the sensitivity of an MPA network for habitat-forming cold-water corals in the northeast Atlantic to changes in larval dispersal driven by atmospheric cycles and larval behaviour. Trajectories of Lophelia pertusa larvae were strongly correlated to the North Atlantic Oscillation (NAO), the dominant pattern of interannual atmospheric circulation variability over the northeast Atlantic. Variability in trajectories significantly altered network connectivity and source-sink dynamics, with positive phase NAO conditions producing a well-connected but asymmetrical network connected from west to east. Negative phase NAO produced reduced connectivity, but notably some larvae tracked westward-flowing currents towards coral populations on the mid-Atlantic ridge. Graph theoretical metrics demonstrate critical roles played by seamounts and offshore banks in larval supply and maintaining connectivity across the network. Larval longevity and behaviour mediated dispersal and connectivity, with shorter lived and passive larvae associated with reduced connectivity. We conclude that the existing MPA network is vulnerable to atmospheric-driven changes in ocean circulation.

Vertical Motion Changes Related to North-East Brazil Rainfall Variability: a GCM Simulation

NASA Astrophysics Data System (ADS)

Roucou, Pascal; Oribe Rocha de Aragão, José; Harzallah, Ali; Fontaine, Bernard; Janicot, Serge

1996-08-01

The atmospheric structure over north-east Brazil during anomalous rainfall years is studied in the 11 levels of the outputs of the Laboratoire de Météorologie Dynamique atmospheric general circulation model (LMD AGCM). Seven 19-year simulations were performed using observed sea-surface temperature (SST) corresponding to the period 1970- 1988. The ensemble mean is calculated for each month of the period, leading to an ensemble-averaged simulation. The simulated March-April rainfall is in good agreement with observations. Correlations of simulated rainfall and three SST indices relative to the equatorial Pacific and northern and southern parts of the Atlantic Ocean exhibit stronger relationships in the simulation than in the observations. This is particularly true with the SST gradient in the Atlantic (Atlantic dipole). Analyses on 200 ;hPa velocity potential, vertical velocity, and vertical integral of the zonal component of mass flux are performed for years of abnormal rainfall and positive/negative SST anomalies in the Pacific and Atlantic oceans in March-April during the rainy season over the Nordeste region. The results at 200 hPa show a convergence anomaly over Nordeste and a divergence anomaly over the Pacific concomitant with dry seasons associated with warm SST anomalies in the Pacific and warm (cold) waters in the North (South) Atlantic. During drought years convection inside the ITCZ indicated by the vertical velocity exhibits a displacement of the convection zone corresponding to a northward migration of the ITCZ. The east-west circulation depicted by the zonal divergent mass flux shows subsiding motion over Nordeste and ascending motion over the Pacific in drought years, accompanied by warm waters in the eastern Pacific and warm/cold waters in northern/southern Atlantic. Rainfall variability of the Nordeste rainfall is linked mainly to vertical motion and SST variability through the migration of the ITCZ and the east-west circulation.

An electron microscopic study of bacteriophages from marine waters

NASA Astrophysics Data System (ADS)

Frank, Hermann; Moebus, Karlheinz

1987-12-01

The morphology of 75 bacteriophage strains isolated from water samples collected in the North Sea or in the northern Atlantic was studied by electron microscopy. Only tailed phages were observed (bradley groups A, B, and C). According to structural similarities, the strains are ascribed to 12 groups, 5 of which comprise types of marine phages not reported before. Four of these 5 groups include phage types that have not been detected from any other source. Among the phages isolated from northern Atlantic water a high incidence was observed of strains the particles of which have long appendages. Certain types of the northern Atlantic phages investigated were derived only from samples collected either east or west of the Azores. This finding agrees with former observations pointing to the existence of different populations of closely related bacteria east and west, respectively, of the northern Mid-Atlantic Ridge.

Analysing the teleconnection systems affecting the climate of the Carpathian Basin

NASA Astrophysics Data System (ADS)

Kristóf, Erzsébet; Bartholy, Judit; Pongrácz, Rita

2017-04-01

Nowadays, the increase of the global average near-surface air temperature is unequivocal. Atmospheric low-frequency variabilities have substantial impacts on climate variables such as air temperature and precipitation. Therefore, assessing their effects is essential to improve global and regional climate model simulations for the 21st century. The North Atlantic Oscillation (NAO) is one of the best-known atmospheric teleconnection patterns affecting the Carpathian Basin in Central Europe. Besides NAO, we aim to analyse other interannual-to-decadal teleconnection patterns, which might have significant impacts on the Carpathian Basin, namely, the East Atlantic/West Russia pattern, the Scandinavian pattern, the Mediterranean Oscillation, and the North-Sea Caspian Pattern. For this purpose primarily the European Centre for Medium-Range Weather Forecasts' (ECMWF) ERA-20C atmospheric reanalysis dataset and multivariate statistical methods are used. The indices of each teleconnection pattern and their correlations with temperature and precipitation will be calculated for the period of 1961-1990. On the basis of these data first the long range (i. e. seasonal and/or annual scale) forecast ability is evaluated. Then, we aim to calculate the same indices of the relevant teleconnection patterns for the historical and future simulations of Coupled Model Intercomparison Project Phase 5 (CMIP5) models and compare them against each other using statistical methods. Our ultimate goal is to examine all available CMIP5 models and evaluate their abilities to reproduce the selected teleconnection systems. Thus, climate predictions for the 21st century for the Carpathian Basin may be improved using the best-performing models among all CMIP5 model simulations.

Role of the circulation on the anthropogenic CO2 inventory in the North-East Atlantic: A climatological analysis

NASA Astrophysics Data System (ADS)

Carracedo, L. I.; Pérez, F. F.; Gilcoto, M.; Velo, A.; Padín, A.; Rosón, G.

2018-02-01

Climatology-based storage rate of anthropogenic CO2 (Cant, referred to year 2000) in the North-East Atlantic (53 ± 9 kmol s-1, 0.020 ± 0.003 Pg-C yr-1) is described on annual mean terms. Cant advection (32 ± 14 kmol s-1) occurs mostly in the upper 1800 m and contributes to 60% of the Cant storage rate. The Azores and Portugal Currents act as 'Cant streams' importing 389 ± 90 kmol s-1, most of which recirculates southwards with the Canary Current (-214 ± 34 kmol s-1). The Azores Counter Current (-79 ± 36 kmol s-1) and the northward-flowing Mediterranean Water advective branch (-31 ± 12 kmol s-1) comprise secondary Cant export routes. By means of Cant transport decomposition, we find horizontal circulation to represent 11% of the Cant storage rate, while overturning circulation is the main driver (48% of the Cant storage rate). Within the domain of this study, overturning circulation is a key mechanism by which Cant in the upper layer (0-500 dbar) is drawdown (74 ± 14 kmol s-1) to intermediate levels (500-2000 dbar), and entrained (37 ± 7 kmol s-1) into the Mediterranean Outflow Water to form Mediterranean Water. This newly formed water mass partly exports Cant to the North Atlantic at a rate of -39 ± 9 kmol s-1 and partly contributes to the Cant storage in the North-East Atlantic (with up to 0.015 ± 0.006 Pg-C yr-1). Closing the Cant budget, 40% of the Cant storage in the North-East Atlantic is attributable to anthropogenic CO2 uptake from the atmosphere (21 ± 10 kmol s-1).

Local and regional effects of large scale atmospheric circulation patterns on winter wind power output in Western Europe

NASA Astrophysics Data System (ADS)

Zubiate, Laura; McDermott, Frank; Sweeney, Conor; O'Malley, Mark

2014-05-01

Recent studies (Brayshaw, 2009, Garcia-Bustamante, 2010, Garcia-Bustamante, 2013) have drawn attention to the sensitivity of wind speed distributions and likely wind energy power output in Western Europe to changes in low-frequency, large scale atmospheric circulation patterns such as the North Atlantic Oscillation (NAO). Wind speed variations and directional shifts as a function of the NAO state can be larger or smaller depending on the North Atlantic region that is considered. Wind speeds in Ireland and the UK for example are approximately 20 % higher during NAO + phases, and up to 30 % lower during NAO - phases relative to the long-term (30 year) climatological means. By contrast, in southern Europe, wind speeds are 15 % lower than average during NAO + phases and 15 % higher than average during NAO - phases. Crucially however, some regions such as Brittany in N.W. France have been identified in which there is negligible variability in wind speeds as a function of the NAO phase, as observed in the ERA-Interim 0.5 degree gridded reanalysis database. However, the magnitude of these effects on wind conditions is temporally and spatially non-stationary. As described by Comas-Bru and McDermott (2013) for temperature and precipitation, such non-stationarity is caused by the influence of two other patterns, the East Atlantic pattern, (EA), and the Scandinavian pattern, (SCA), which modulate the position of the NAO dipole. This phenomenon has also implications for wind speeds and directions, which has been assessed using the ERA-Interim reanalysis dataset and the indices obtained from the PC analysis of sea level pressure over the Atlantic region. In order to study the implications for power production, the interaction of the NAO and the other teleconnection patterns with local topography was also analysed, as well as how these interactions ultimately translate into wind power output. The objective is to have a better defined relationship between wind speed and power output at a local level and a tool that wind farm developers could use to inform site selection. A particular priority was to assess how the potential wind power outputs over a 25-30 year windfarm lifetime in less windy, but resource-stable regions, compare with those from windier but more variable sites.

Secondary contact and asymmetrical gene flow in a cosmopolitan marine fish across the Benguela upwelling zone

PubMed Central

Reid, K; Hoareau, T B; Graves, J E; Potts, W M; dos Santos, S M R; Klopper, A W; Bloomer, P

2016-01-01

The combination of oceanographic barriers and habitat heterogeneity are known to reduce connectivity and leave specific genetic signatures in the demographic history of marine species. However, barriers to gene flow in the marine environment are almost never impermeable which inevitably allows secondary contact to occur. In this study, eight sampling sites (five along the South African coastline, one each in Angola, Senegal and Portugal) were chosen to examine the population genetic structure and phylogeographic history of the cosmopolitan bluefish (Pomatomus saltatrix), distributed across a large South-east Atlantic upwelling zone. Molecular analyses were applied to mtDNA cytochrome b, intron AM2B1 and 15 microsatellite loci. We detected uncharacteristically high genetic differentiation (FST 0.15–0.20; P<0.001) between the fish sampled from South Africa and the other sites, strongly influenced by five outlier microsatellite loci located in conserved intergenic regions. In addition, differentiation among the remaining East Atlantic sites was detected, although mtDNA indicated past isolation with subsequent secondary contact between these East Atlantic populations. We further identified secondary contact, with unidirectional gene flow from South Africa to Angola. The directional contact is likely explained by a combination of the northward flowing offshore current and endogenous incompatibilities restricting integration of certain regions of the genome and limiting gene flow to the south. The results confirm that the dynamic system associated with the Benguela current upwelling zone influences species distributions and population processes in the South-east Atlantic. PMID:27436525

Secondary contact and asymmetrical gene flow in a cosmopolitan marine fish across the Benguela upwelling zone.

PubMed

Reid, K; Hoareau, T B; Graves, J E; Potts, W M; Dos Santos, S M R; Klopper, A W; Bloomer, P

2016-11-01

The combination of oceanographic barriers and habitat heterogeneity are known to reduce connectivity and leave specific genetic signatures in the demographic history of marine species. However, barriers to gene flow in the marine environment are almost never impermeable which inevitably allows secondary contact to occur. In this study, eight sampling sites (five along the South African coastline, one each in Angola, Senegal and Portugal) were chosen to examine the population genetic structure and phylogeographic history of the cosmopolitan bluefish (Pomatomus saltatrix), distributed across a large South-east Atlantic upwelling zone. Molecular analyses were applied to mtDNA cytochrome b, intron AM2B1 and 15 microsatellite loci. We detected uncharacteristically high genetic differentiation (F ST 0.15-0.20; P<0.001) between the fish sampled from South Africa and the other sites, strongly influenced by five outlier microsatellite loci located in conserved intergenic regions. In addition, differentiation among the remaining East Atlantic sites was detected, although mtDNA indicated past isolation with subsequent secondary contact between these East Atlantic populations. We further identified secondary contact, with unidirectional gene flow from South Africa to Angola. The directional contact is likely explained by a combination of the northward flowing offshore current and endogenous incompatibilities restricting integration of certain regions of the genome and limiting gene flow to the south. The results confirm that the dynamic system associated with the Benguela current upwelling zone influences species distributions and population processes in the South-east Atlantic.

Late Cretaceous-Paleocene strike-slip faults along the East Greenland margin (63°N to 75°N): constraints for the North East Atlantic opening

NASA Astrophysics Data System (ADS)

Guarnieri, P.

2012-04-01

The East Greenland margin is a long stretch starting from 60°N up to 81°N in a distance of almost 3000 km. It represents the conjugate of the European margin now separated by the North East Atlantic (NEA). After a long period of E-W extension and almost N-S oriented rift basins since Early Cretaceous, separation between Greenland and Europe began at 55 Ma following a NE-SW oriented line of breakup and the emplacement of the North Atlantic Igneous Province (NAIP). Post-breakup thermal subsidence followed in the Eocene, and the Oligocene initiated a period of plate re-organization together with the initial separation of Jan Mayen microcontinent, a complex tectonic history with inversion structures and uplifts along both the East Greenland and European margins. The effect of this history is represented by exhumed sedimentary basins, dyke swarms, fault systems, intrusive centers, shield volcanoes and plateau lavas constituting highest mountain of Greenland with some peaks up to 3700 m (e.g. Watkins Bjerge). During expeditions for fieldwork in East Greenland (2009 to 2011) to collect new geological and structural data related to the North East Atlantic tectonics, four areas were visited: Skjoldungen 63°N, Kangerlussuaq 68°N, Traill Ø 72°N and Wollaston Forland 75°N. More than 1000 measurement of fault-slip data for structural analysis along major faults were collected and helicopter flights to collect oblique pictures for 3D-photogeology and 3D-mapping were taken. Kinematic analysis of brittle deformation associated with Late Cretaceous-Paleocene rift shows strike-slip movements. Palaeo-stress tensors reconstructed from fault-slip data highlight a NE-SW maximum horizontal stress in a strike-slip tectonic setting along the entire East Greenland margin (Guarnieri 2011a; Guarnieri 2011b; Guarnieri et al. 2011). Structural data show clear evidence for oblique rifting that corresponds in time to the "volcanic rift" (61-55 Ma) with in some cases the magmatic segmentation of macro-dyke complexes or the activation of major shear zones with strike-slip movements. Oblique rifting and strike-slip deformation along the East Greenland margin reflect the progressive clockwise shift, from W-E to NW-SE, of the separation trend between Greenland and Europe probably in response to the opening of the Labrador Sea.

Variability of cyclones over the North Atlantic and Europe since 1871

NASA Astrophysics Data System (ADS)

Welker, C.; Martius, O.

2012-04-01

The scarce availability of long-term atmospheric data series has so far limited the analysis of low-frequency activity and intensity changes of cyclones over the North Atlantic and Europe. A novel reanalysis product, the Twentieth Century Reanalysis (20CR; Compo et al., 2011), spanning 1871 to present, offers potentially a very valuable resource for the analysis of the decadal-scale variability of cyclones over the North Atlantic sector and Europe. In the 20CR, only observations of synoptic surface pressure were assimilated. Monthly sea surface temperature and sea ice distributions served as boundary conditions. An Ensemble Kalman Filter assimilation technique was applied. "First guess" fields were obtained from an ensemble (with 56 members) of short-range numerical weather prediction forecasts. We apply the cyclone identification algorithm of Wernli and Schwierz (2006) to this data set, i.e. to each individual ensemble member. This enables us to give an uncertainty estimation of our findings. We find that 20CR shows a temporally relatively homogeneous representation of cyclone activity over Europe and great parts of the North Atlantic. Pronounced decadal-scale variability is found both in the frequency and intensity of cyclones over the North Atlantic and Europe. The low-frequency variability is consistently represented in all ensemble members. Our analyses indicate that in the past approximately 140 years the variability of cyclone activity and intensity over the North Atlantic and Europe can principally be associated with the North Atlantic Oscillation and secondary with a pattern similar to the East Atlantic pattern. Regionally however, the correlation between cyclone activity and these dominant modes of variability changes over time. Compo, G. P., J. S. Whitaker, P. D. Sardeshmukh, N. Matsui, R. J. Allan, X. Yin, B. E. Gleason, R. S. Vose, G. Rutledge, P. Bessemoulin, S. Brönnimann, M. Brunet, R. I. Crouthamel, A. N. Grant, P. Y. Groisman, P. D. Jones, M. C. Kruk, A. C. Kruger, G. J. Marshall, M. Maugeri, H. Y. Mok, Ø. Nordli, T. F. Ross, R. M. Trigo, X. L. Wang, S. D. Woodruff, and S. J. Worley, 2011: The Twentieth Century Reanalysis project. Quarterly J. Roy. Meteorol. Soc., 137, 1-28. Wernli, H. and C. Schwierz, 2006: Surface cyclones in the ERA-40 dataset (1958-2001). Part I: Novel identification method and global climatology. J. Atmos. Sci., 63, 2486-2507.

Oil, the Arab--Israel dispute, and the industrial world: horizons of crisis. [Book: 20 papers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurewitz, J.C.

1976-01-01

This book is the product of a multinational project, sponsored by the Middle East Institute of Columbia University in cooperation with the World Peace Foundation (Boston), the Atlantic Institute for Internal Affairs (Paris), and the Asia-Pacific Association of Japan (Tokyo). It focuses on the principal unresolved issues of the energy crisis, the Arab-Israel dispute, and their tangled effects that feed back to and feed upon relations with the North Atlantic countries and Japan. Since almost all the papers were originally presented for discussion to three study groups--North American (US and Canada), Western European, and Japanese--it was possible to assess themore » domestic interests and pressures that inhibit and those that promote cooperation among the major nonsocialist industrial states and to illuminate the linkages between the domestic influences and the national policymaking processes. This symposium comes into focus as a study, not of one issue, but of the intersection of three. For analytical purposes, the energy crisis and the Arab-Israel dispute are decoupled. The decoupled analysis forms the subject matter of the first two parts of the book. Thereafter, the Middle East problem of popular perception is reconstituted. The chapters of the third part inquire into major effects in the Middle East of the mixing of oil and politics and speculate on likely developments in the coming decade of this still potent mixture. The fourth part considers primary aspects of the evolving patterns of international political economy, as influenced by the energy crisis or its linkage to the Arab-Israel dispute.« less

Dispersal and population connectivity in the deep North Atlantic estimated from physical transport processes

NASA Astrophysics Data System (ADS)

Etter, Ron J.; Bower, Amy S.

2015-10-01

Little is known about how larvae disperse in deep ocean currents despite how critical estimates of population connectivity are for ecology, evolution and conservation. Estimates of connectivity can provide important insights about the mechanisms that shape patterns of genetic variation. Strong population genetic divergence above and below about 3000 m has been documented for multiple protobranch bivalves in the western North Atlantic. One possible explanation for this congruent divergence is that the Deep Western Boundary Current (DWBC), which flows southwestward along the slope in this region, entrains larvae and impedes dispersal between the upper/middle slope and the lower slope or abyss. We used Lagrangian particle trajectories based on an eddy-resolving ocean general circulation model (specifically FLAME - Family of Linked Atlantic Model Experiments) to estimate the nature and scale of dispersal of passive larvae released near the sea floor at 4 depths across the continental slope (1500, 2000, 2500 and 3200 m) in the western North Atlantic and to test the potential role of the DWBC in explaining patterns of genetic variation on the continental margin. Passive particles released into the model DWBC followed highly complex trajectories that led to both onshore and offshore transport. Transport averaged about 1 km d-1 with dispersal kernels skewed strongly right indicating that some larvae dispersed much greater distances. Offshore transport was more likely than onshore and, despite a prevailing southwestward flow, some particles drifted north and east. Dispersal trajectories and estimates of population connectivity suggested that the DWBC is unlikely to prevent dispersal among depths, in part because of strong cross-slope forces induced by interactions between the DWBC and the deeper flows of the Gulf Stream. The strong genetic divergence we find in this region of the Northwest Atlantic is therefore likely driven by larval behaviors and/or mortality that limit dispersal, or local selective processes (both pre and post-settlement) that limit recruitment of immigrants from some depths.

The Caspian Sea Catchment influenced by Atlantic Teleconnections in CESM1.2.2 and Observations

NASA Astrophysics Data System (ADS)

Nandini, S. D.; Prange, M.; Schulz, M.

2017-12-01

The Caspian Sea (CS) is the world's largest inland sea and located within a closed (endorheic) drainage basin [ 37°-47N, 47°-54°E]. It has undergone dynamic variations (>3 m) during the past century with huge impacts on the economy, ecosystem and livelihood of coastal people. The origin of these variations as well as future changes are disputable. Here, we examine the impact of the major seasonal North Atlantic teleconnection patterns, the North Atlantic Oscillation (NAO) and the East Atlantic pattern (EA) on Caspian hydroclimate variability from 1850-2100 CE. Five Numerical experiments at different atmospheric grid resolutions (2° and 1°) and atmospheric model versions (CAM4 and CAM5) are carried out with the coupled Community Earth System Model (CESM1.2.2). Results reveal the 1° CESM1.2.2 CAM5 captures DJF NAO (46.5%) and EA (13.4%), agreeing well with observational data (1850-2000). The DJF NAO has a strong influence on the DJF temperature, rainfall and evaporation minus precipitation (E-P) over the Caspian sub-basins (Volga, Ural, Terek and Kura). Furthermore, 1° model climate projections (2020-2100 CE) are performed with different Representative Concentration Pathways (RCP4.5 and RCP8.5) to examine likely changes in the NAO and EA and their influence on the Caspian catchment. The NAO under the RCP4.5 and RCP8.5 scenarios remains the leading mode with the highest variance and influences E-P with increased precipitation over the Volga basin and increased evaporation over the Caspian Sea. The above canceling effects act on the hydroclimate variability in the Caspian sub-basins. Moreover, it is indicated that no substantial change is predicted in the CSL by the year 2100. Keywords: North Atlantic Oscillation (NAO), CESM1.2.2 resolutions, Evaporation minus Precipitation (E-P), RCP4.5, RCP8.5

33 CFR 334.1480 - Vieques Passage and Atlantic Ocean, off east coast of Puerto Rico and coast of Vieques Island...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Ocean, off east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. 334.1480... east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. (a) The restricted areas. (1) A strip, 1,500 yards wide, off the naval reservation shoreline along the east coast of Puerto...

33 CFR 334.1480 - Vieques Passage and Atlantic Ocean, off east coast of Puerto Rico and coast of Vieques Island...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Ocean, off east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. 334.1480... east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. (a) The restricted areas. (1) A strip, 1,500 yards wide, off the naval reservation shoreline along the east coast of Puerto...

33 CFR 334.1480 - Vieques Passage and Atlantic Ocean, off east coast of Puerto Rico and coast of Vieques Island...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Ocean, off east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. 334.1480... east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. (a) The restricted areas. (1) A strip, 1,500 yards wide, off the naval reservation shoreline along the east coast of Puerto...

33 CFR 334.1480 - Vieques Passage and Atlantic Ocean, off east coast of Puerto Rico and coast of Vieques Island...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Ocean, off east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. 334.1480... east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. (a) The restricted areas. (1) A strip, 1,500 yards wide, off the naval reservation shoreline along the east coast of Puerto...

33 CFR 334.1480 - Vieques Passage and Atlantic Ocean, off east coast of Puerto Rico and coast of Vieques Island...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Ocean, off east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. 334.1480... east coast of Puerto Rico and coast of Vieques Island; naval restricted areas. (a) The restricted areas. (1) A strip, 1,500 yards wide, off the naval reservation shoreline along the east coast of Puerto...

Basin-scale variability in plankton biomass and community metabolism in the sub-tropical North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Harrison, W. G.; Arístegui, J.; Head, E. J. H.; Li, W. K. W.; Longhurst, A. R.; Sameoto, D. D.

Three trans-Atlantic oceanographic surveys (Nova Scotia to Canary Islands) were carried out during fall 1992 and spring 1993 to describe the large-scale variability in hydrographic, chemical and biological properties of the upper water column of the subtropical gyre and adjacent waters. Significant spatial and temporal variability characterized a number of the biological pools and rate processes whereas others were relatively invariant. Systematic patterns were observed in the zonal distribution of some properties. Most notable were increases (eastward) in mixed-layer temperature and salinity, depths of the nitracline and chlorophyll- a maximum, regenerated production (NH 4 uptake) and bacterial production. Dissolved inorganic carbon (DIC) concentrations, phytoplankton biomass, mesozooplankton biomass and new production (NO 3 uptake) decreased (eastward). Bacterial biomass, primary production, and community respiration exhibited no discernible zonal distribution patterns. Seasonal variability was most evident in hydrography (cooler/fresher mixed-layer in spring), and chemistry (mixed-layer DIC concentration higher and nitracline shallower in spring) although primary production and bacterial production were significantly higher in spring than in fall. In general, seasonal variability was greater in the west than in the east; seasonality in most properties was absent west of Canary Islands (˜20°W). The distribution of autotrophs could be reasonably well explained by hydrography and nutrient structure, independent of location or season. Processes underlying the distribution of the microheterophs, however, were less clear. Heterotrophic biomass and metabolism was less variable than autotrophs and appeared to dominate the upper ocean carbon balance of the subtropical North Atlantic in both fall and spring. Geographical patterns in distribution are considered in the light of recent efforts to partition the ocean into distinct "biogeochemical provinces".

Variability modes of precipitation along a Central Mediterranean area and their relations with ENSO, NAO, and other climatic patterns

NASA Astrophysics Data System (ADS)

Kalimeris, Anastasios; Ranieri, Ezio; Founda, Dimitra; Norrant, Caroline

2017-12-01

This study analyses a century-long set of precipitation time series in the Central Mediterranean (encompassing the Greek Ionian and the Italian Puglia regions) and investigates the statistically significant modes of the interannual precipitation variability using efficient methods of spectral decomposition. The statistical relations and the possible physical couplings between the detected modes and the global or hemispheric patterns of climatic variability (the El Niño Southern Oscillation or ENSO, the North Atlantic Oscillation or NAO, the East Atlantic or EA, the Scandinavian or SCAND, and others) were examined in the time-frequency domain and low-order synchronization events were sought. Significant modes of precipitation variability were detected in the Taranto Gulf and the southern part of the Greek Ionian region at the sub-decadal scales (mostly driven by the SCAND pattern) and particularly at the decadal and quasi-decadal scales, where strong relations found with the ENSO activity (under complex implications of EA and NAO) prior to the 1930s or after the early-1970s. The precipitation variations in the Adriatic stations of Puglia are dominated by significant bi-decadal modes which found to be coherent with the ENSO activity and also weakly related with the Atlantic Ocean sea surface temperature intrinsic variability. Additionally, important discontinuities characterize the evolution of precipitation in certain stations of the Taranto Gulf and the Greek Ionian region during the early-1960s and particularly during the early-1970s, followed by significant reductions in the mean annual precipitation. These discontinuities seem to be associated with regional effects of NAO and SCAND, probably combined with the impact of the 1970s climatic shift in the Pacific and the ENSO variability.

The east coast petroleum province: Science and society

USGS Publications Warehouse

Jordan, R.R.

1999-01-01

The U.S. Atlantic offshore, especially the mid-Atlantic, was an exciting exploration area from the 1970s into the 1980s. Much pioneering 'frontier' activity in both scientific and policy matters occurred in this area. Although production was not achieved, objective geological evidence indicates that the province does have potential. Major population centers of the mid-Atlantic area demand large amounts of energy and enormous amounts of crude and product are shipped through East Coast waters. Nevertheless, exploration has been shut down by moratoria, environmental concerns, and international pricing. It is suggested that the province will be revisited in the future and that the geologic and environmental information that has been generated at great cost should be preserved for use by the next generation of explorationists and policy-makers.

The subtle role of climate change on population genetic structure in Canada lynx.

PubMed

Row, Jeffrey R; Wilson, Paul J; Gomez, Celine; Koen, Erin L; Bowman, Jeff; Thornton, Daniel; Murray, Dennis L

2014-07-01

Anthropogenically driven climatic change is expected to reshape global patterns of species distribution and abundance. Given recent links between genetic variation and environmental patterns, climate change may similarly impact genetic population structure, but we lack information on the spatial and mechanistic underpinnings of genetic-climate associations. Here, we show that current genetic variability of Canada lynx (Lynx canadensis) is strongly correlated with a winter climate gradient (i.e. increasing snow depth and winter precipitation from west-to-east) across the Pacific-North American (PNO) to North Atlantic Oscillation (NAO) climatic systems. This relationship was stronger than isolation by distance and not explained by landscape variables or changes in abundance. Thus, these patterns suggest that individuals restricted dispersal across the climate boundary, likely in the absence of changes in habitat quality. We propose habitat imprinting on snow conditions as one possible explanation for this unusual phenomenon. Coupling historical climate data with future projections, we also found increasingly diverging snow conditions between the two climate systems. Based on genetic simulations using projected climate data (2041-2070), we predicted that this divergence could lead to a threefold increase in genetic differentiation, potentially leading to isolated east-west populations of lynx in North America. Our results imply that subtle genetic structure can be governed by current climate and that substantive genetic differentiation and related ecological divergence may arise from changing climate patterns. © 2014 John Wiley & Sons Ltd.

THE EFFECTS OF THE COASTAL ENVIRONMENT ON THE ATMOSPHERIC MERCURY CYCLE

EPA Science Inventory

Atmospheric mercury (Hg) species were investigated on the East Coast of Florida during June 2000. The site was impacted by air mass transport from the Atlantic Ocean and Southern Florida. Periods with atmospheric transport from the Atlantic were characterized by low concentra...

Evidence for a bi-partition of the Younger Dryas Stadial in East Asia associated with inversed climate characteristics compared to Europe.

PubMed

Schlolaut, Gordon; Brauer, Achim; Nakagawa, Takeshi; Lamb, Henry F; Tyler, Jonathan J; Staff, Richard A; Marshall, Michael H; Bronk Ramsey, Christopher; Bryant, Charlotte L; Tarasov, Pavel E

2017-03-31

The Younger Dryas Stadial (YDS) was an episode of northern hemispheric cooling which occurred within the Last Glacial Interglacial Transition (LGIT). A major driver for the YDS climate was a weakening of the Atlantic Meridional Overturning Circulation (AMOC). It has been inferred that the AMOC began to strengthen mid-YDS, producing a bipartite structure of the YDS in records from continental Europe. These records imply that the polar front and westerlies shifted northward, producing a warmer second phase of the YDS in Europe. Here we present multi-proxy data from the sediments of Lake Suigetsu (Japan), as evidence that a related bi-partition of the YDS also occurred in East Asia. Besides showing for the first time that the bi-partition was not limited to the North Atlantic/European region, the data also imply a climatic dipole between Europe and East Asia since the cold-warm characteristics are reversed at Lake Suigetsu. We suggest that changes in eastward moisture transport from the North Atlantic are the primary mechanism by which the teleconnection can be explained.

Measurements of dimethyl sulfide and H2S over the western North Atlantic and the tropical Atlantic

NASA Technical Reports Server (NTRS)

Andreae, T. W.; Andreae, M. O.; Bingemer, H. G.; Leck, C.

1993-01-01

Airborne measurements of DMS and H2S were made off the east coast of the United States and over the tropical Atlantic off Brazil. Samples were collected through a fluorinated ethylene propylene Teflon inlet manifold. Dimethyl sulfide (DMS) was preconcentrated onto gold wool and analyzed by gas chromatography/flame photometric detection. H2S was collected on AgNO3-impregnated filters and determined by fluorescence quenching. Use of a new scrubber material (cotton) to remove negative interference on DMS measurements was investigated. Comparison with a Na2CO3/Anakrom scrubber gave good overall agreement. Only under extreme conditions, e.g., on flight 9 (continental air mass, low humidity, high O3, and low DMS values) did Na2CO3 show noticeable loss of DMS compared to cotton. On most flights, especially in marine air masses with high humidity and relatively low O3, the results from both scrubbers agreed well with each other and with other instruments used during the intercalibration. Off the U.S. East Coast, DMS levels showed strong dependence on air mass origin with high values (up to 83 ppt) in marine tropical air masses and low values (10-20 ppt) in continental and polar air. Over the tropical Atlantic, DMS ranged over 20-100 ppt in the mixed layer. Nighttime values were a factor of 1.6-2.3 higher than daytime levels. DMS decreased with altitude to less than 1 ppt at 4000 m. H2S in the mixed layer off the U.S. East Coast ranged from 10 to 200 ppt. Significant influence from terrestrial and pollution sources was evident. H2S in air masses originating over the eastern seaboard was much higher than in continental polar air or over the remote tropical continents. In contrast, over the tropical Atlantic, concentrations were very low (5-10 ppt), typical of truly marine air. Night/day ratios were about 1.4. No significant geographical variability was seen in H2S levels over the tropical Atlantic. The correlation of atmospheric Rn-222 and H2S was significant, with both being higher off the U.S. East Coast than over the tropical Atlantic.

Atlantic salmon and eastern oyster breeding programs at the National Cold Water Marine Aquaculture Center

USDA-ARS?s Scientific Manuscript database

The USDA-ARS National Cold Water Marine Aquaculture Center (NCWMAC) focuses on the coldwater marine aquaculture industry's highest priority research needs including development of improved genetic stocks. Coldwater aquaculture production has potential for expansion, and both Atlantic salmon and East...

77 FR 22216 - Drawbridge Operation Regulations; Atlantic Intracoastal Waterway, Fort Lauderdale, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-13

... Boulevard (SR 838) Bridge, mile 1062.6; and the East Las Olas Bridge, mile 1064. The deviations are... Boulevard (SR 838) Bridge, mile 1062.6. The vertical clearance of the East Sunrise Boulevard (SR 838) Bridge...

50 CFR 622.224 - Area closures to protect South Atlantic corals.

Code of Federal Regulations, 2014 CFR

2014-10-01

... east of the NASA Vehicle Assembly Building, Cape Canaveral, FL). (b) Oculina Bank—(1) HAPC. The Oculina...., on the east by the 100-fathom (183-m) contour, as shown on the latest edition of NOAA chart 11460...

50 CFR 622.224 - Area closures to protect South Atlantic corals.

Code of Federal Regulations, 2013 CFR

2013-10-01

... east of the NASA Vehicle Assembly Building, Cape Canaveral, FL). (b) Oculina Bank—(1) HAPC. The Oculina...., on the east by the 100-fathom (183-m) contour, as shown on the latest edition of NOAA chart 11460...

Meiofauna assemblages of the Condor Seamount (North-East Atlantic Ocean) and adjacent deep-sea sediments

NASA Astrophysics Data System (ADS)

Zeppilli, Daniela; Bongiorni, Lucia; Cattaneo, Antonio; Danovaro, Roberto; Santos, Ricardo Serrão

2013-12-01

Seamounts are currently considered hotspots of biodiversity and biomass for macro- and megabenthic taxa, but knowledge of meiofauna is still limited. Studies have revealed the existence of highly diverse meiofauna assemblages; however most data are mainly qualitative or focused only on specific groups, thus preventing comparisons among seamounts and with other deep-sea areas. This study, conducted on Condor Seamount (Azores, North-East Atlantic Ocean), describes variation in abundance, biomass, community structure and biodiversity of benthic meiofauna from five sites located on the Condor Seamount: and one site away from the seamount. While the summit of the seamount hosted the highest alpha biodiversity, the flanks and the bases showed a rich meiofauna assemblage in terms of abundance and biomass. The observed marked differences in grain size composition of sediments reflected the oceanographic conditions impacting different sectors of the Condor seamount, and could play an important role in the spatial distribution of different meiofaunal taxa. Trophic conditions (biochemical composition of organic matter) explained 78% of the variability in the meiofauna biomass pattern while sediment grain influenced the vertical distribution of meiofauna and only partially explained meiofaunal taxa composition. This study provides a further advancement in the knowledge of meiofaunal communities of seamounts. Only a deeper understanding of the whole benthic communities (including meiofauna) will allow to elaborate effective management and conservation tools for seamount ecosystems.

Water mass circulation and weathering inputs in the Labrador Sea based on coupled Hf-Nd isotope compositions and rare earth element distributions

NASA Astrophysics Data System (ADS)

Filippova, Alexandra; Frank, Martin; Kienast, Markus; Rickli, Jörg; Hathorne, Ed; Yashayaev, Igor M.; Pahnke, Katharina

2017-02-01

The Labrador Sea is one of the key areas for deep water formation driving the Atlantic thermohaline circulation and thus plays an important role in Northern Hemisphere climatic fluctuations. In order to better constrain the overturning processes and the origins of the distinct water masses, combined dissolved Hf-Nd isotopic compositions and rare earth element (REE) distribution patterns were obtained from four water depth profiles along a section across the Labrador Sea. These were complemented by one surface sample off the southern tip of Greenland, three shallow water samples off the coast of Newfoundland, and two deep water samples off Nova Scotia. Although light REEs are markedly enriched in the surface waters off the coast of Newfoundland compared to north Atlantic waters, the REE concentration profiles are essentially invariant throughout the water column across the Labrador Sea. The hafnium concentrations of surface waters exhibit a narrow range between 0.6 and 1 pmol/kg but are not significantly higher than at depth. Neodymium isotope signatures (ɛNd) vary from unradiogenic values between -16.8 and -14.9 at the surface to more radiogenic values near -11.0 at the bottom of the Labrador Sea mainly reflecting the advection of the Denmark Strait Overflow Water and North East Atlantic Deep Water, the signatures of which are influenced by weathering contributions from Icelandic basalts. Unlike Nd, water column radiogenic Hf isotope signatures (ɛHf) are more variable representing diverse weathering inputs from the surrounding landmasses. The least radiogenic seawater ɛHf signatures (up to -11.7) are found in surface waters close to Greenland and near the Canadian margin. This reflects the influence of recirculating Irminger Current Waters, which are affected by highly unradiogenic inputs from Greenland. A three to four ɛHf unit difference is observed between Denmark Strait Overflow Water (ɛHf ∼ -4) and North East Atlantic Deep Water (ɛHf ∼ -0.1), although their source waters have essentially the same ɛNd signature. This most likely reflects different weathering signals of hafnium delivered to Denmark Strait Overflow Water and North East Atlantic Deep Water (incongruent weathering of old rocks from Greenland versus basaltic rocks from Iceland). In addition, the ɛHf data resolve two layers within the main body of Labrador Sea Water not visible in the ɛNd distribution, which are shallow Labrador Sea Water (ɛHf ∼ -2) and deep Labrador Sea Water (ɛHf ∼ -4.5). The latter layer was formed between the late 1980's and mid 1990's during the last cold state of the Labrador Sea and underwent substantial modification since its formation through the admixture of Irminger Water, Iceland Slope Water and North East Atlantic Deep Water, which is reflected in its less radiogenic ɛHf signature. The overall behavior of Hf in the water column suggests its higher sensitivity to local changes in weathering inputs on annual to decadal timescales. Although application of Hf isotopes as a tracer for global water mass mixing is complicated by their susceptibility to incongruent weathering inputs they are a promising tracer of local processes in restricted basins such as the Labrador Sea.

Climate and vegetation changes around the Atlantic Ocean resulting from changes in the meridional overturning circulation during deglaciation

NASA Astrophysics Data System (ADS)

Handiani, D.; Paul, A.; Dupont, L.

2012-07-01

The Bølling-Allerød (BA, starting ~ 14.5 ka BP) is one of the most pronounced abrupt warming periods recorded in ice and pollen proxies. The leading explanation of the cause of this warming is a sudden increase in the rate of deepwater formation in the North Atlantic Ocean and the resulting effect on the heat transport by the Atlantic Meridional Overturning Circulation (AMOC). In this study, we used the University of Victoria (UVic) Earth System-Climate Model (ESCM) to run simulations, in which a freshwater perturbation initiated a BA-like warming period. We found that under present climate conditions, the AMOC intensified when freshwater was added to the Southern Ocean. However, under Heinrich event 1 (HE1, ~ 16 ka BP) climate conditions, the AMOC only intensified when freshwater was extracted from the North Atlantic Ocean, possibly corresponding to an increase in evaporation or a decrease in precipitation in this region. The intensified AMOC led to a warming in the North Atlantic Ocean and a cooling in the South Atlantic Ocean, resembling the bipolar seesaw pattern typical of the last glacial period. In addition to the physical response, we also studied the simulated vegetation response around the Atlantic Ocean region. Corresponding with the bipolar seesaw hypothesis, the rainbelt associated with the Intertropical Convergence Zone (ITCZ) shifted northward and affected the vegetation pattern in the tropics. The most sensitive vegetation area was found in tropical Africa, where grass cover increased and tree cover decreased under dry climate conditions. An equal but opposite response to the collapse and recovery of the AMOC implied that the change in vegetation cover was transient and robust to an abrupt climate change such as during the BA period, which is also supported by paleovegetation data. The results are in agreement with paleovegetation records from Western tropical Africa, which also show a reduction in forest cover during this time period. Further agreement between data and model results was found for the uplands of North America and Southern Europe, where grassland along with warm and dry climates were simulated. However, our model simulated vegetation changes in South and North America that were much smaller than reconstructed. Along the west and east coast of North America we simulated drier vegetation than the pollen records suggest.

Simulated variability of the Atlantic meridional overturning circulation

NASA Astrophysics Data System (ADS)

Bentsen, M.; Drange, H.; Furevik, T.; Zhou, T.

To examine the multi-annual to decadal scale variability of the Atlantic Meridional Overturning Circulation (AMOC) we conducted a four-member ensemble with a daily reanalysis forced, medium-resolution global version of the isopycnic coordinate ocean model MICOM, and a 300-years integration with the fully coupled Bergen Climate Model (BCM). The simulations of the AMOC with both model systems yield a long-term mean value of 18 Sv and decadal variability with an amplitude of 1-3 Sv. The power spectrum of the inter-annual to decadal scale variability of the AMOC in BCM generally follows the theoretical red noise spectrum, with indications of increased power near the 20-years period. Comparison with observational proxy indices for the AMOC, e.g. the thickness of the Labrador Sea Water, the strength of the baroclinic gyre circulation in the North Atlantic Ocean, and the surface temperature anomalies along the mean path of the Gulf Stream, shows similar trends and phasing of the variability, indicating that the simulated AMOC variability is robust and real. Mixing indices have been constructed for the Labrador, the Irminger and the Greenland-Iceland-Norwegian (GIN) seas. While convective mixing in the Labrador and the GIN seas are in opposite phase, and linked to the NAO as observations suggest, the convective mixing in the Irminger Sea is in phase with or leads the Labrador Sea. Newly formed deep water is seen as a slow, anomalous cold and fresh, plume flowing southward along the western continental slope of the Atlantic Ocean, with a return flow of warm and saline water on the surface. In addition, fast-travelling topographically trapped waves propagate southward along the continental slope towards equator, where they go east and continue along the eastern rim of the Atlantic. For both types of experiments, the Northern Hemisphere sea level pressure and 2 m temperature anomaly patterns computed based on the difference between climate states with strong and weak AMOC yields a NAO-like pattern with intensified Icelandic low and Azores high, and a warming of 0.25-0.5 °C of the central North Atlantic sea-surface temperature (SST). The reanalysis forced simulations indicate a coupling between the Labrador Sea Water production rate and an equatorial Atlantic SST index in accordance with observations. This coupling is not identified in the coupled simulation.

Characteristics and present trends of wave extremes in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Pino, Cosimo; Lionello, Piero; Galati, Maria Barbara

2010-05-01

Wind generated surface waves are an important factor characterizing marine storminess and the marine environment. This contribution considers characteristics and trends of SWH (Significant Wave Height) extremes (both high and low extremes, such as dead calm duration are analyzed). The data analysis is based on a 44-year long simulation (1958-2001) of the wave field in the Mediterranean Sea. The quality of the model simulation is controlled using satellite data. The results show the different characteristics of the different parts of the basin with the variability being higher in the western (where the highest values are produced) than in the eastern areas of the basin (where absence of wave is a rare condition). In fact, both duration of storms and of dead calm episodes is larger in the east than in the west part of the Mediterranean. The African coast and the southern Ionian Sea are the areas were exceptional values of SWH are expected to occur in correspondence with exceptional meteorological events. Significant trends of storm characteristics are present only in sparse areas and suggest a decrease of both storm intensity and duration (a marginal increase of storm intensity is present in the center of the Mediterranean). The statistics of extremes and high SWH values is substantially steady during the second half of the 20th century. The influence of the large-scale teleconnection patterns (TlcP) that are known to be relevant for the Mediterranean climate on the intensity and spatial distribution of extreme SWH (Significant Wave Height) has been investigated. The analysis was focused on the monthly scale analysing the variability of links along the annual cycle. The considered TlcP are the North Atlantic Oscillation, the East-Atlantic / West-Russian pattern and the Scandinavian pattern and their effect on the intensity and the frequency of high/low SWH conditions. The results show it is difficult to establish a dominant TlcP for SWH extremes, because all 4 patterns considered are important for at least few months in the year and none of them is important for the whole year. High extremes in winter and fall are more influenced by the TlcPs than in other seasons and low extremes.

Temporal and spatial variation in habitat characteristics of Tilefish (Lopholatilus Chamaeleonticeps) off the east coast of Florida

USGS Publications Warehouse

Able, Kenneth W.; Grimes, Churchill B.; Jones, Robert; Twichell, David C.

1993-01-01

The tilefish, Lopholatilus chamaeleonticeps, constructs burrows in carbonate sediments off the central east coast of Florida at similar temperatures (8.6-15.4°C) and in similar sediment textures (high proportion of silts and clays) to conspecifics in the Mid-Atlantic Bight. The depths at which we observed tile fish off Florida (150-290 m), based on submersible observations and sidescan sonar operations during 1983 and 1984, were similar to those recorded in 1975-1977 (137-266 m) before the inception of the directed fishery. Both are similar to the range observed in the Mid-Atlantic Bight although tilefish there can be found at shallower and slightly deeper depths (80-305 m). The largest burrows off Florida (1.5-m diameter) were smaller than those observed in the Mid-Atlantic Bight (up to 5 m). The behavior of tile fish around the burrow and the invertebrates and fishes co-inhabiting the burrows off Florida are nearly identical to those in the Mid-Atlantic Bight. Despite the relatively narrow annual temperature range observed off Florida, abrupt changes in temperatures (+6°C) occurred over a 48-h period based on thermograph records. Our observations, and those of others from several areas along the U.S. east coast, suggest that this species probably constructs burrows throughout its geographic range, and that temperature and sediment composition largely determine its distribution. Exclusion experiments off Florida, along with prior removal experiments in the Mid-Atlantic Bight, indicate that tilefish construct and maintain the burrows.

Influence of finite-time Lyapunov exponents on winter precipitation over the Iberian Peninsula

NASA Astrophysics Data System (ADS)

Garaboa-Paz, Daniel; Lorenzo, Nieves; Pérez-Muñuzuri, Vicente

2017-05-01

Seasonal forecasts have improved during the last decades, mostly due to an increase in understanding of the coupled ocean-atmosphere dynamics, and the development of models able to predict the atmosphere variability. Correlations between different teleconnection patterns and severe weather in different parts of the world are constantly evolving and changing. This paper evaluates the connection between winter precipitation over the Iberian Peninsula and the large-scale tropospheric mixing over the eastern Atlantic Ocean. Finite-time Lyapunov exponents (FTLEs) have been calculated from 1979 to 2008 to evaluate this mixing. Our study suggests that significant negative correlations exist between summer FTLE anomalies and winter precipitation over Portugal and Spain. To understand the mechanisms behind this correlation, summer anomalies of the FTLE have also been correlated with other climatic variables such as the sea surface temperature (SST), the sea level pressure (SLP) or the geopotential. The East Atlantic (EA) teleconnection index correlates with the summer FTLE anomalies, confirming their role as a seasonal predictor for winter precipitation over the Iberian Peninsula.

Prevalence of marine debris in marine birds from the North Atlantic.

PubMed

Provencher, Jennifer F; Bond, Alexander L; Hedd, April; Montevecchi, William A; Muzaffar, Sabir Bin; Courchesne, Sarah J; Gilchrist, H Grant; Jamieson, Sarah E; Merkel, Flemming R; Falk, Knud; Durinck, Jan; Mallory, Mark L

2014-07-15

Marine birds have been found to ingest plastic debris in many of the world's oceans. Plastic accumulation data from necropsies findings and regurgitation studies are presented on 13 species of marine birds in the North Atlantic, from Georgia, USA to Nunavut, Canada and east to southwest Greenland and the Norwegian Sea. Of the species examined, the two surface plungers (great shearwaters Puffinus gravis; northern fulmars Fulmarus glacialis) had the highest prevalence of ingested plastic (71% and 51%, respectively). Great shearwaters also had the most pieces of plastics in their stomachs, with some individuals containing as many of 36 items. Seven species contained no evidence of plastic debris. Reporting of baseline data as done here is needed to ensure that data are available for marine birds over time and space scales in which we see changes in historical debris patterns in marine environments (i.e. decades) and among oceanographic regions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Seasonal prediction of hurricane activity reaching the coast of the United States.

PubMed

Saunders, Mark A; Lea, Adam S

2005-04-21

Much of the property damage from natural hazards in the United States is caused by landfalling hurricanes--strong tropical cyclones that reach the coast. For the southeastern Atlantic coast of the US, a statistical method for forecasting the occurrence of landfalling hurricanes for the season ahead has been reported, but the physical mechanisms linking the predictor variables to the frequency of hurricanes remain unclear. Here we present a statistical model that uses July wind anomalies between 1950 and 2003 to predict with significant and useful skill the wind energy of US landfalling hurricanes for the following main hurricane season (August to October). We have identified six regions over North America and over the east Pacific and North Atlantic oceans where July wind anomalies, averaged between heights of 925 and 400 mbar, exhibit a stationary and significant link to the energy of landfalling hurricanes during the subsequent hurricane season. The wind anomalies in these regions are indicative of atmospheric circulation patterns that either favour or hinder evolving hurricanes from reaching US shores.

77 FR 29472 - Surety Companies Acceptable on Federal Bonds-Termination: Atlantic Bonding Company, Inc.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-17

..., Financial Accounting and Services Division, Surety Bond Branch, 3700 East-West Highway, Room 6F01, Hyattsville, MD 20782. Dated: May 8, 2012. Laura Carrico, Director, Financial Accounting and Services Division...--Termination: Atlantic Bonding Company, Inc. AGENCY: Financial Management Service, Fiscal Service, Department...

8. VIEW FROM NORTHERN FOOT BRIDGE ABOVE INTAKE STRUCTURE EAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW FROM NORTHERN FOOT BRIDGE ABOVE INTAKE STRUCTURE EAST TOWARD UPSTREAM BANK OF NORTH SIDE OF DAM - Upper Doughty Dam, 200 feet west of Garden State Parkway, 1.7 miles west of Absecon, Egg Harbor City, Atlantic County, NJ

7. VIEW FROM SOUTHERN FOOT BRIDGE ABOVE INTAKE STRUCTURE EAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. VIEW FROM SOUTHERN FOOT BRIDGE ABOVE INTAKE STRUCTURE EAST TOWARD UPSTREAM BANK OF SOUTH SIDE OF DAM - Upper Doughty Dam, 200 feet west of Garden State Parkway, 1.7 miles west of Absecon, Egg Harbor City, Atlantic County, NJ

Wintertime re-ventilation of the East Greenland Current's Atlantic-origin Overflow Water in the western Iceland Sea

NASA Astrophysics Data System (ADS)

Våge, Kjetil; Håvik, Lisbeth; Papritz, Lukas; Spall, Michael; Moore, Kent

2017-04-01

The Deep Western Boundary Current constitutes the lower limb of the Atlantic Meridional Overturning Circulation, and, as such, is a crucial component of the Earth's climate system. The largest and densest contribution to the current stems from the overflow plume that passes through Denmark Strait. A main source of Denmark Strait Overflow Water (DSOW) is the East Greenland Current (EGC). The DSOW transported by the EGC originates from the Atlantic inflow into the Nordic Seas. This is then transformed into Atlantic-origin Overflow Water while progressing northward through the eastern part of the Nordic Seas. Here we show, using measurements from autonomous gliders deployed from fall 2015 to spring 2016, that the Atlantic-origin Overflow Water transported toward Denmark Strait by the EGC was re-ventilated while transiting the western Iceland Sea in winter. In summer, this region is characterized by an upper layer of cold, fresh Polar Surface Water that is thought to prevent convection. But in fall and winter this fresh water mass is diverted toward the Greenland shelf by enhanced northerly winds, which results in a water column that is preconditioned for convection. Severe heat loss from the ocean to the atmosphere offshore of the ice edge subsequently causes the formation of deep mixed layers. This further transforms the Atlantic-origin Overflow Water and impacts the properties of the DSOW, and hence the deepest and densest component of the lower limb of the Atlantic Meridional Overturning Circulation.

78 FR 33221 - Special Local Regulation; Annual Swim Around Key West, Atlantic Ocean and Gulf of Mexico; Key...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-04

... Fort Zach State Park, North through Key West Harbor, East through Flemming Cut, South on Cow Key... State Park, North through Key West Harbor, East through Flemming Cut, South on Cow Key Channel and West...

Interannual Rainfall Variability in North-East Brazil: Observation and Model Simulation

NASA Astrophysics Data System (ADS)

Harzallah, A.; Rocha de Aragão, J. O.; Sadourny, R.

1996-08-01

The relationship between interannual variability of rainfall in north-east Brazil and tropical sea-surface temperature is studied using observations and model simulations. The simulated precipitation is the average of seven independent realizations performed using the Laboratoire de Météorologie Dynamique atmospheric general model forced by the 1970-1988 observed sea-surface temperature. The model reproduces very well the rainfall anomalies (correlation of 091 between observed and modelled anomalies). The study confirms that precipitation in north-east Brazil is highly correlated to the sea-surface temperature in the tropical Atlantic and Pacific oceans. Using the singular value decomposition method, we find that Nordeste rainfall is modulated by two independent oscillations, both governed by the Atlantic dipole, but one involving only the Pacific, the other one having a period of about 10 years. Correlations between precipitation in north-east Brazil during February-May and the sea-surface temperature 6 months earlier indicate that both modes are essential to estimate the quality of the rainy season.

75 FR 55304 - Proposed Information Collection; Comment Request; Atlantic Sea Scallops Amendment 10 Data Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-10

... IFQ vessels; sector proposals for IFQ vessels and industry participants; sector operations plans for... minutes; cost recovery, 2 hours; sector proposals, 150 hours; sector operations plans, 100 hours; IFQ... Exclusive Economic Zone (EEZ) off the East Coast under the Atlantic Sea Scallop Fishery Management Plan (FMP...

76 FR 10778 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Coastal Migratory Pelagic...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-28

... Migratory Pelagic Resources of the Gulf of Mexico and South Atlantic; Closure AGENCY: National Marine...: Temporary rule; closure. SUMMARY: NMFS closes the commercial sector for king mackerel in the Florida east coast subzone. This closure is necessary to protect the Gulf king mackerel resource. DATES: The closure...

Chinese Tallow (Triadica sebifera (L.) Small) Population expansion in Louisiana, East Texas, and Mississippi

Treesearch

Sonja N. Oswalt

2010-01-01

Chinese tallow (Triadica sebifera) is a nonnative invasive species with high fecundity rates that has naturalized from the coastal prairies of east Texas along the Gulf and Atlantic coasts as far north as North Carolina. Population differences were computed for two forest inventory periods (mid-1990s and late 2000s) in Louisiana, east Texas, and Mississippi using data...

Storm-tracks interannual variability and large-scale climate modes

NASA Astrophysics Data System (ADS)

Liberato, Margarida L. R.; Trigo, Isabel F.; Trigo, Ricardo M.

2013-04-01

In this study we focus on the interannual variability and observed changes in northern hemisphere mid-latitude storm-tracks and relate them to large scale atmospheric circulation variability modes. Extratropical storminess, cyclones dominant paths, frequency and intensity have long been the object of climatological studies. The analysis of storm characteristics and historical trends presented here is based on the cyclone detecting and tracking algorithm first developed for the Mediterranean region (Trigo et al. 1999) and recently extended to a larger Euro-Atlantic region (Trigo 2006). The objective methodology, which identifies and follows individual lows as minima in SLP fields, fulfilling a set of conditions regarding the central pressure and the pressure gradient, is applied to the northern hemisphere 6-hourly geopotential data at 1000 hPa from the 20th Century Reanalyses (20CRv2) project and from reanalyses datasets provided by the European Centre for Medium-Range Weather Forecasts (ECMWF): ERA-40 and ERA Interim reanalyses. First, we assess the interannual variability and cyclone frequency trends for each of the datasets, for the 20th century and for the period between 1958 and 2002 using the highest spatial resolution available (1.125° x 1.125°) from the ERA-40 data. Results show that winter variability of storm paths, cyclone frequency and travel times is in agreement with the reported variability in a number of large-scale climate patterns (including the North Atlantic Oscillation, the East Atlantic Pattern and the Scandinavian Pattern). In addition, three storm-track databases are built spanning the common available extended winter seasons from October 1979 to March 2002. Although relatively short, this common period allows a comparison of systems represented in reanalyses datasets with distinct horizontal resolutions. This exercise is mostly focused on the key areas of cyclogenesis and cyclolysis and main cyclone characteristics over the northern hemisphere. Trigo IF., TD Davies, GR Bigg (1999) Objective climatology of cyclones in the Mediterranean region. J. Climate 12: 1685-1696. Trigo IF (2006) Climatology and interannual variability of storm-tracks in the Euro-Atlantic sector: a comparison between ERA-40 and NCEP/NCAR reanalyses. Clim. Dyn. 26: 127-143.

Skillful prediction of hot temperature extremes over the source region of ancient Silk Road.

PubMed

Zhang, Jingyong; Yang, Zhanmei; Wu, Lingyun

2018-04-27

The source region of ancient Silk Road (SRASR) in China, a region of around 150 million people, faces a rapidly increased risk of extreme heat in summer. In this study, we develop statistical models to predict summer hot temperature extremes over the SRASR based on a timescale decomposition approach. Results show that after removing the linear trends, the inter-annual components of summer hot days and heatwaves over the SRASR are significantly related with those of spring soil temperature over Central Asia and sea surface temperature over Northwest Atlantic while their inter-decadal components are closely linked to those of spring East Pacific/North Pacific pattern and Atlantic Multidecadal Oscillation for 1979-2016. The physical processes involved are also discussed. Leave-one-out cross-validation for detrended 1979-2016 time series indicates that the statistical models based on identified spring predictors can predict 47% and 57% of the total variances of summer hot days and heatwaves averaged over the SRASR, respectively. When the linear trends are put back, the prediction skills increase substantially to 64% and 70%. Hindcast experiments for 2012-2016 show high skills in predicting spatial patterns of hot temperature extremes over the SRASR. The statistical models proposed herein can be easily applied to operational seasonal forecasting.

The American Political Intervention in the Conflict in the Dutch East Indies 1945-1949

DTIC Science & Technology

2009-06-12

Harry S. Truman Presidential Library KNIL Koninklijk Nederlands Indisch Leger (Royal Netherlands Indies Army) NATO North Atlantic Treaty Organization......colony and called it Netherlands-Indies ( Nederlands -Indie). In the English language, it remained Dutch East Indies or Netherlands Indies. The Dutch

Worldwide Emerging Environmental Issues Affecting the U.S. Military. June 2009

DTIC Science & Technology

2009-06-01

9 7.7.4 Melting Glaciers and Sea Ice…………………………………………………..9 7.7.5 Rising Sea Levels………………………………………….……………..…….9 7.7.6...animals from North Sea fulmars, to Northeast Atlantic plankton. UNEP suggests several strategies to curb marine The Millennium Project International...regional seas included in the report––Baltic Sea , Black Sea , Caspian Sea , East Asian seas , East African seas , Mediterranean, Northeast Atlantic

Uncovering the role of the East Asian jet stream and heterogeneities in atmospheric rivers affecting the western United States.

PubMed

Zhang, Wei; Villarini, Gabriele

2018-01-30

Atmospheric rivers (ARs) exert major socioeconomic repercussions along the US West Coast by inducing heavy rainfall, flooding, strong winds, and storm surge. Despite the significant societal and economic repercussions of these storms, our understanding of the physical drivers responsible for their interannual variability is limited, with different climate modes identified as possible mechanisms. Here we show that the Pacific-Japan (PJ) teleconnections/patterns and the East Asian subtropical jet (EASJ) exhibit a strong linkage with the total frequency of ARs making landfall over the western United States, much stronger than the other potential climate modes previously considered. While our findings indicate that the PJ pattern and EASJ are the most relevant climate modes driving the overall AR activity, we also uncover heterogeneities in AR tracks. Specifically, we show that not all ARs making landfall along the West Coast come from a single population, but rather that it is possible to stratify these storms into three clusters. While the PJ pattern and EASJ are major drivers of AR activity for two clusters, the cluster that primarily affects the US Southwest is largely driven by other climate modes [El Niño Southern Oscillation (ENSO), the Atlantic meridional mode (AMM), the Pacific-North America (PNA) teleconnection pattern, and the North Pacific Gyre Oscillation (NPGO)]. Therefore, important regional differences exist and this information can substantially enhance our ability to predict and prepare for these storms and their impacts.

Retrieval of Absorbing Aerosols Above Clouds retrieval over the South East Atlantic Ocean from MSG/SEVIRI

NASA Astrophysics Data System (ADS)

Peers, F.; Haywood, J. M.; Francis, P. N.; Meyer, K.; Platnick, S. E.

2017-12-01

Over the South East Atlantic Ocean, biomass burning aerosols from Southern Africa are frequently observed above clouds during fire season. However, the quantification of their interactions with both radiations and clouds remains uncertain because of a lack of information on aerosol properties and on their interaction process. In the last decade, methods have been developed to retrieve aerosol optical properties above clouds from satellite measurements, especially over the South East Atlantic Ocean. Most of these methods have been applied to polar orbiting instruments which prevent the analysis of aerosols and clouds at a sub-daily scale. With its wide spatial coverage and its high temporal resolution, the geostationary instrument SEVIRI, on board the MSG platform, offers a unique opportunity to monitor aerosols in this region and to evaluate their impact on clouds and their radiative effects. In this study, we will investigate the possibility of retrieving simultaneously aerosol and cloud properties (i.e. aerosol and cloud optical thicknesses and cloud droplet effective radius) when aerosols are located above clouds. The retrieved properties will then be compared with the ones obtained from MODIS [Meyer et al., 2015] as well as observations from the CLARIFY-2017 field campaign.

Tropical Hydroclimate Change during Heinrich Stadial 1: An Integrative Proxy-Model Synthesis

NASA Astrophysics Data System (ADS)

Lawman, A. E.; Sun, T.; Shanahan, T. M.; Di Nezio, P. N.; Gomez, K.; Piatrunia, N.; Sun, C.; Wu, X.; Kageyama, M.; Merkel, U.; Otto-Bliesner, B. L.; Abe-Ouchi, A.; Lohmann, G.; Singarayer, J. S.

2017-12-01

We explore the response of tropical climate to abrupt cooling of the North Atlantic (NA) during Heinrich Stadial 1 (HS1) combining paleoclimate proxies with model simulations. A total of 146 published paleoclimate records from tropical locations are used to categorize whether HS1 was wetter, drier, or unchanged relative to a deglacial baseline state. Only records with sufficient resolution to resolve HS1 and sufficient length to characterize the deglacial trend are considered. This synthesis reveals large-scale patterns of hydroclimate change relative to glacial conditions, confirming previously reported weaker Indian summer monsoon, a wetter southern Africa, and drying over the Caribbean. Our synthesis also reveals large-scale drying over the Maritime continent as well as wetter conditions in northern Australia and southern tropical South America. Our reinterpretation of the available proxy data reveals far more complexity and uncertainties for equatorial East Africa, a region that appears to straddle a pattern of dryer conditions to the north and wetter conditions to the south. Overall, these patterns of hydroclimate change depart from a southward shift of the Inter Tropical Convergence Zone (ITCZ), particularly outside the tropical Atlantic. We explore mechanisms driving these changes using a multi-model ensemble of "hosing" simulations performed relative to glacial conditions. The models show robust weakening of the Afro-Asian Monsoon, which we attribute to ventilation of colder mid-latitude air. Not all models simulate the remaining patterns inferred from the proxy data. The best-agreeing models indicate that cooling over the tropical NA and the Caribbean may be essential to communicate the response to the global tropics. This response can induce warming over the tropical South Atlantic via the wind-evaporation-SST feedback, driving wetter conditions in South Africa and tropical South America. Cooling over the Caribbean is communicated to the Pacific over the Central American isthmus resulting in an El Niño-like pattern accompanied by drying over the Maritime Continent - as seen in the proxy data. Together these results show a dominant role for altered tropical SST gradients driving changes in tropical rainfall, and a lesser role for inter-hemispheric shifts in the ITCZ.

Assimilation of TOPEX/POSEIDON altimeter data into a circulation model of the North Atlantic

NASA Astrophysics Data System (ADS)

Blayo, E.; Verron, J.; Molines, J. M.

1994-12-01

Assimilation experiments were conducted using the first 12 months of TOPEX/POSEIDON (T/P) altimeter measurements in a multilayered quasi-geostrophic model of the North Atlantic between 20°N and 60°N. These experiments demonstrate the feasibility of using T/P data to control a basin-scale circulation model by means of an assimilation procedure. Moreover, they allow us to recreate the four-dimensional behavior of the North Atlantic Ocean during the year October 1992-September 1993 and to improve our knowledge and understanding of such circulation patterns. For this study we used a four-layer quasigeostrophic model of high horizontal resolution (1/6° in latitude and longitude). The assimilation procedure used is an along-track, sequential, nudging technique. The evolution of the model general circulation is described and analyzed from a deterministic and statistical point of view, with special emphasis on the Gulf Stream area. The gross features of the North Atlantic circulation in terms of mean transport and circulation are reproduced, such as the path, penetration and recirculation of the Gulf Stream, and its meandering throughout the eastern basin. The North Atlantic Drift is, however, noticeably underestimated. A northern meander of the north wall of the Gulf Stream above the New England Seamount Chain is present for most of the year, while, just downstream, the southern part of the jet is subject to a 100-km southeastward deflection. The Azores current is shown to remain stable and to shift southward with time from the beginning of December 1992 to the end of April 1993, the amplitude of the shift being about 2°. The computation of the mean latitude of the Gulf Stream as a function of time shows an abrupt shift from a northern position to a southern position in January, and a reverse shift, from a southern position to a northern position, in July. Finally, some issues are addressed concerning the comparison of assimilation experiments using T/P data and Geosat data. The first results show that the T/P simulations are more energetic than the Geosat simulations, especially east of the Mid-Atlantic Ridge, for every wavelength from 50 km to 500 km. This property is also verified in the deep ocean. The predicted abyssal circulation is indeed more energetic in the T/P case, which is more in accordance with what we know of the real ocean. Moreover, the good T/P altimeter coverage near the coasts greatly improves the model eddy kinetic energy levels in these areas, especially east of 25°W.

Climate variability and the Icelandic marine ecosystem

NASA Astrophysics Data System (ADS)

Astthorsson, Olafur S.; Gislason, Astthor; Jonsson, Steingrimur

2007-11-01

This paper describes the main features of the Icelandic marine ecosystem and its response to climate variations during the 20th century. The physical oceanographic character and faunal composition in the southern and western parts of the Icelandic marine ecosystem are different from those in the northern and the eastern areas. The former areas are more or less continuously bathed by warm and saline Atlantic water while the latter are more variable and influenced by Atlantic, Arctic and even Polar water masses to different degrees. Mean annual primary production is higher in the Atlantic water than in the more variable waters north and east of Iceland, and higher closer to land than farther offshore. Similarly, zooplankton production is generally higher in the Atlantic water than in the waters north and east of Iceland. The main spawning grounds of most of the exploited fish stocks are in the Atlantic water south of the country while nursery grounds are off the north coast. In the recent years the total catch of fish and invertebrates has been in the range of 1.6-2.4 million ton. Capelin ( Mallotus villosus) is the most important pelagic stock and cod ( Gadus morhua) is by far the most important demersal fish stock. Whales are an important component of the Icelandic marine ecosystem, and Icelandic waters are an important habitat for some of the largest seabird populations in the Northeast Atlantic. In the waters to the north and east of Iceland, available information suggests the existence of a simple bottom-up controlled food chain from phytoplankton through Calanus, capelin and to cod. Less is known about the structure of the more complex southern part of the ecosystem. The Icelandic marine ecosystem is highly sensitive to climate variations as demonstrated by abundance and distribution changes of many species during the warm period in the 1930s, the cold period in the late 1960s and warming observed during the recent years. Some of these are highlighted in the paper.

Sensitivity of two Iberian lakes to North Atlantic atmospheric circulation modes

NASA Astrophysics Data System (ADS)

Hernández, Armand; Trigo, Ricardo M.; Pla-Rabes, Sergi; Valero-Garcés, Blas L.; Jerez, Sonia; Rico-Herrero, Mayte; Vega, José C.; Jambrina-Enríquez, Margarita; Giralt, Santiago

2015-12-01

The North Atlantic Oscillation (NAO) exerts a major influence on the climate of the North Atlantic region. However, other atmospheric circulation modes (ACMs), such as the East Atlantic (EA) and Scandinavian (SCAND) patterns, also play significant roles. The dynamics of lakes on the Iberian Peninsula are greatly controlled by climatic parameters, but their relationship with these various ACMs has not been investigated in detail. In this paper, we analyze monthly meteorological and limnological long-term datasets (1950-2011 and 1992-2011, respectively) from two lakes on the northern and central Iberian Peninsula (Sanabria and Las Madres) to develop an understanding of the seasonal sensitivity of these freshwater systems to the NAO, EA and SCAND circulation modes. The limnological variability within Lake Sanabria is primarily controlled by fluctuations in the seasonal precipitation and wind, and the primary ACMs associated with the winter limnological processes are the NAO and the SCAND modes, whereas only the EA mode appears to weakly influence processes during the summer. However, Lake Las Madres is affected by precipitation, wind and, to a lesser extent, temperature, whereas the ACMs have less influence. Therefore, we aim to show that the lakes of the Iberian Peninsula are sensitive to these ACMs. The results presented here indicate that the lake dynamics, in some cases, have a higher sensitivity to variations in the ACMs than single local meteorological variables. However, certain local features, such as geography, lake morphology and anthropic influences, are crucial to properly record the signals of these ACMs.

Paleoenvironmental Reconstruction of the North Atlantic Current Variations from MIS 3 to Holocene Based on Multiproxy Record from the North-East Scotland Continental Margin.

NASA Astrophysics Data System (ADS)

Ovsepyan, Y.; Tikhonova, A.; Novichkova, E.; Gupta, R. M.; Korsun, S.; Matul, A.

2017-12-01

In order to reconstruct the history of water mass interaction between the North Atlantic and the Nordic Seas since MIS 3 to the present, the sediment core from the North-East Scotland continental slope was investigated. The site of core AI-3521 (59°30.009 N, 7°20.062 E) from the 1051 m water depth is located beneath the pathway of the North Atlantic current which transports warm and saline Atlantic surface water to the Norwegian Sea. The age model of the sequence is based on stable isotope record of benthic Cassidulina neoteretis and planktic Neogloboquadrina pachyderma sin. and Globigerina bulloides. The Holocene interval of the upper 1.5 m is characterized by high sedimentation rates and the high biodiversity of microfauna. The distribution of ice rafted debris and CaCO3 content; benthic and planktic foraminiferal assemblages; oxygen, carbon and boron isotopes, Mg/Ca ratio were used to reconstruct the regional paleoceanographic conditions (bioproductivity, temperature, salinity) and to compare with the paleoclimatic events in the subpolar North Atlantic in the frame of the global environmental changes during the Late Pleistocene and Holocene. The research was supported by Russian Science Foundation projects 16-47-02009 and 14-50-00095.

Ocean array alters view of Atlantic conveyor

NASA Astrophysics Data System (ADS)

Kornei, Katherine

2018-02-01

Oceanographers have put a stethoscope on the coursing circulatory system of the Atlantic Ocean, and they have found a skittish pulse that's surprisingly strong in the waters east of Greenland—discoveries that should improve climate models. The powerful currents known as the Atlantic meridional overturning circulation (AMOC) are an engine in Earth's climate. The AMOC's shallower limbs—which include the Gulf Stream—move warm water from the tropics northward, warming Western Europe. In the north, the waters cool and sink, forming deeper limbs that transport the cold water back south—and sequester anthropogenic carbon in the process. Last week, at the American Geophysical Union's Ocean Sciences meeting, scientists presented the first data from an array of instruments moored in the subpolar North Atlantic, a $35 million, seven-nation project known as the Overturning in the Subpolar North Atlantic Program (OSNAP). Since 2004, researchers have gathered data from another array, at 26°N, stretching from Florida to Africa. But OSNAP is the first to monitor the circulation farther north, where a critical aspect of the overturning occurs. The observations reveal unexpected eddies and strong variability in the AMOC currents. They also show that the currents east of Greenland contribute the most to the total AMOC flow. Climate models, on the other hand, have emphasized the currents west of Greenland in the Labrador Sea.

Assessment of undiscovered oil and gas resources of the East Coast Mesozoic basins of the Piedmont, Blue Ridge Thrust Belt, Atlantic Coastal Plain, and New England Provinces, 2011

USGS Publications Warehouse

Milici, Robert C.; Coleman, James L.; Rowan, Elisabeth L.; Cook, Troy A.; Charpentier, Ronald R.; Kirschbaum, Mark A.; Klett, Timothy R.; Pollastro, Richard M.; Schenk, Christopher J.

2012-01-01

During the early opening of the Atlantic Ocean in the Mesozoic Era, numerous extensional basins formed along the eastern margin of the North American continent from Florida northward to New England and parts of adjacent Canada. The basins extend generally from the offshore Atlantic continental margin westward beneath the Atlantic Coastal Plain to the Appalachian Mountains. Using a geology-based assessment method, the U.S. Geological Survey estimated a mean undiscovered natural gas resource of 3,860 billion cubic feet and a mean undiscovered natural gas liquids resource of 135 million barrels in continuous accumulations within five of the East Coast Mesozoic basins: the Deep River, Dan River-Danville, and Richmond basins, which are within the Piedmont Province of North Carolina and Virginia; the Taylorsville basin, which is almost entirely within the Atlantic Coastal Plain Province of Virginia and Maryland; and the southern part of the Newark basin (herein referred to as the South Newark basin), which is within the Blue Ridge Thrust Belt Province of New Jersey. The provinces, which contain these extensional basins, extend across parts of Georgia, South Carolina, North Carolina, Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut, and Massachusetts.

Environmental Assessment for the 920th Rescue Wing Beddown Patrick Air Force Base, Florida

DTIC Science & Technology

2005-10-01

covers approximately 2002 acres and is bounded by the Atlantic Ocean on the east and the Banana River on the west (see Figure 2). There is little...along the Atlantic Ocean (see Figure 1). From the dunes, the site gently slopes northwest toward the Banana River shoreline. Currently the 45th...920th RQW COMPLEX ATLANTIC OCEAN B A N A ..?,. BANANA RIVER .. , N "’ A LEGEND N011:: SOURCE: U.S.G.S. 7.5 MINUTE TOPOGRAPHIC

Space Radar Image of Lisbon, Portugal

NASA Technical Reports Server (NTRS)

1994-01-01

This radar image of Lisbon, Portugal illustrates the different land use patterns that are present in coastal Portugal. Lisbon, the national capital, lies on the north bank of the Rio Tejo where the river enters the Atlantic Ocean. The city center appears as the bright area in the center of the image. The green area west of the city center is a large city park called the Parque Florestal de Monsanto. The Lisbon Airport is visible east of the city. The Rio Tejo forms a large bay just east of the city. Many agricultural fields are visible as a patchwork pattern east of the bay. Suburban housing can be seen on the southern bank of the river. Spanning the river is the Ponte 25 de Abril, a large suspension bridge similar in architecture to San Francisco's Golden Gate Bridge. The image was acquired on April 19, 1994 and is centered at 38.8 degrees north latitude, 9.2 degrees west longitude. North is towards the upper right. The image is 50 kilometers by 30 kilometers (31 miles by 19 miles). The colors in this image represent the following radar channels and polarizations: red is L-band, horizontally transmitted and received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. SIR-C/X-SAR, a joint mission of the German, Italian, and the United States space agencies, is part of NASA's Mission to Planet Earth.

Independent Origins of Cultivated Coconut (Cocos nucifera L.) in the Old World Tropics

PubMed Central

Gunn, Bee F.; Baudouin, Luc; Olsen, Kenneth M.

2011-01-01

As a portable source of food, water, fuel, and construction materials, the coconut (Cocos nucifera L.) played a fundamental role in human migrations and the development of civilization across the humid tropics. Here we investigated the coconut's domestication history and its population genetic structure as it relates to human dispersal patterns. A sample of 1,322 coconut accessions, representing the geographical and phenotypic diversity of the species, was examined using ten microsatellite loci. Bayesian analyses reveal two highly genetically differentiated subpopulations that correspond to the Pacific and Indo-Atlantic oceanic basins. This pattern suggests independent origins of coconut cultivation in these two world regions, with persistent population structure on a global scale despite long-term human cultivation and dispersal. Pacific coconuts show additional genetic substructure corresponding to phenotypic and geographical subgroups; moreover, the traits that are most clearly associated with selection under human cultivation (dwarf habit, self-pollination, and “niu vai” fruit morphology) arose only in the Pacific. Coconuts that show evidence of genetic admixture between the Pacific and Indo-Atlantic groups occur primarily in the southwestern Indian Ocean. This pattern is consistent with human introductions of Pacific coconuts along the ancient Austronesian trade route connecting Madagascar to Southeast Asia. Admixture in coastal east Africa may also reflect later historic Arab trading along the Indian Ocean coastline. We propose two geographical origins of coconut cultivation: island Southeast Asia and southern margins of the Indian subcontinent. PMID:21731660

Independent origins of cultivated coconut (Cocos nucifera L.) in the old world tropics.

PubMed

Gunn, Bee F; Baudouin, Luc; Olsen, Kenneth M

2011-01-01

As a portable source of food, water, fuel, and construction materials, the coconut (Cocos nucifera L.) played a fundamental role in human migrations and the development of civilization across the humid tropics. Here we investigated the coconut's domestication history and its population genetic structure as it relates to human dispersal patterns. A sample of 1,322 coconut accessions, representing the geographical and phenotypic diversity of the species, was examined using ten microsatellite loci. Bayesian analyses reveal two highly genetically differentiated subpopulations that correspond to the Pacific and Indo-Atlantic oceanic basins. This pattern suggests independent origins of coconut cultivation in these two world regions, with persistent population structure on a global scale despite long-term human cultivation and dispersal. Pacific coconuts show additional genetic substructure corresponding to phenotypic and geographical subgroups; moreover, the traits that are most clearly associated with selection under human cultivation (dwarf habit, self-pollination, and "niu vai" fruit morphology) arose only in the Pacific. Coconuts that show evidence of genetic admixture between the Pacific and Indo-Atlantic groups occur primarily in the southwestern Indian Ocean. This pattern is consistent with human introductions of Pacific coconuts along the ancient Austronesian trade route connecting Madagascar to Southeast Asia. Admixture in coastal east Africa may also reflect later historic Arab trading along the Indian Ocean coastline. We propose two geographical origins of coconut cultivation: island Southeast Asia and southern margins of the Indian subcontinent.

Factors Affecting Moulting Patterns of Atlantic Lobster (Homarus americanus) in the East Coast of Canada

NASA Astrophysics Data System (ADS)

Vanderstichel, R.; Thakur, K. K.; Revie, C. W.; Lavallée, J.

2016-02-01

In recent years, there has been a significant increase in the proportion of soft-shelled lobsters caught in Atlantic Canada. Soft-shelled lobsters pose a severe economic challenge to the lobster industry due to low meat yield and poor survivability during holding and transportation. The objectives of this study were to describe the moulting patterns of lobster in Atlantic Canada and to identify factors associated with soft-shelled lobsters. We used routinely collected data by the Atlantic Lobster Moult and Quality monitoring project from a range of locations within two lobster fishing areas in southwestern Nova Scotia. We incorporated environmental (sea surface temperature) and geographical (depth) variables before applied logistic and time-series regression methods to analyze the data. The analyses included more than 119,000 samples from 2004 to 2014. The proportion of soft-shelled lobsters ranged from 9 to 38% during these years. The logistic model demonstrated that stage of moulting, sex of the lobster, level of hemolymph concentration and median depth of the fishing locations were highly associated with the shell hardness of lobsters. This model further indicated that the shell quality was significantly influenced by month of sampling and the fishing areas from which the lobsters were caught, suggesting seasonal and regional differences. Additionally, significant inter-year variability in the shell quality indicated potential impact of climatic variation during these years. This hypothesis is supported by our initial analysis suggesting that the hemolymph concentration is associated with changes in sea surface temperature and ongoing work which evaluates the impact of temperature fluctuation on shell quality will be presented. Findings from this study will be of value to the lobster industry in helping to determine optimal fishing areas and periods, to improve the shell quality of landed lobsters and therefore to increase economic returns.

Interdecadal variability of the Afro-Asian summer monsoon system

NASA Astrophysics Data System (ADS)

Li, Yi; Ding, Yihui; Li, Weijing

2017-07-01

The Afro-Asian summer monsoon is a zonally planetary-scale system, with a large-scale rainbelt covering Africa, South Asia and East Asia on interdecadal timescales both in the past century (1901-2014) and during the last three decades (1979-2014). A recent abrupt change of precipitation occurred in the late 1990s. Since then, the entire rainbelt of the Afro-Asia monsoon system has advanced northwards in a coordinated way. Consistent increases in precipitation over the Huanghe-Huaihe River valley and the Sahel are associated with the teleconnection pattern excited by the warm phase of the Atlantic Multidecadal Oscillation (AMO). A teleconnection wave train, with alternating cyclones/anticyclones, is detected in the upper troposphere. Along the teleconnection path, the configuration of circulation anomalies in North Africa is characterized by coupling of the upper-level anticyclone (divergence) with low-level thermal low pressure (convergence), facilitating the initiation and development of ascending motions in the Sahel. Similarly, in East Asia, a coupled circulation pattern also excites ascending motion in the Huanghe-Huaihe River valley. The synchronous increase in precipitation over the Sahel and Huanghe-Huaihe River valley can be attributed to the co-occurrences and in-phase changes of ascending motion. On the other hand, the warm phase of the AMO results in significant warming in the upper troposphere in North Africa and the northern part of East Asia. Such warming contributes to intensification of the tropical easterly jet through increasing the meridional pressure gradient both at the entrance region (East Asia) and the exit region (Africa). Accordingly, precipitation over the Sahel and Huanghe-Huaihe River valley intensifies, owing to ageostrophic secondary cells. The results of this study provide evidence for a consistent and holistic interdecadal change in the Afro-Asian summer monsoon.

Sandy retired from list of Atlantic Basin tropical cyclone names

Science.gov Websites

2012 Atlantic hurricane season Media Contact Dennis Feltgen 305-229-4404 305-433-1933 (cellular) Share tropical cyclone names April 11, 2013 GOES East image of Hurricane Sandy, Oct. 29, 2012. This NOAA GOES-13 cyclone names by the World Meteorological Organization's hurricane committee because of the extreme

Sensitivity of the summertime tropical Atlantic precipitation distribution to convective parameterization and model resolution in ECHAM6

DOE PAGES

Siongco, Angela Cheska; Hohenegger, Cathy; Stevens, Bjorn

2017-02-09

A realistic simulation of the tropical Atlantic precipitation distribution remains a challenge for atmospheric general circulation models, owing to their too coarse resolution that makes it necessary to parameterize convection. During boreal summer, models tend to underestimate the northward shift of the tropical Atlantic rain belt, leading to deficient precipitation over land and an anomalous precipitation maximum over the west Atlantic ocean. In this study, the model ECHAM6 is used to test the sensitivity of the precipitation biases to convective parameterization and horizontal resolution. Two sets of sensitivity experiments are performed. In the first set of experiments, modifications are appliedmore » to the convection scheme in order to investigate the relative roles of the trigger, entrainment, and closure formulations. In the second set, the model is run at high resolution with low-resolution boundary conditions in order to identify the relative contributions of a high-resolution atmosphere, orography, and surface. Results show that the dry bias over land in the model can be reduced by weakening the entrainment rate over land. Over ocean, it is found that the anomalous precipitation maximum occurs because of model choices that decrease the sensitivity of convection to the monsoon circulation in the east Atlantic. A reduction of the west Atlantic precipitation bias can be achieved by (i) using a moisture convergence closure, (ii) increasing the resolution of orography, or (iii) enhancing the production of deep convection in the east Atlantic. As a result, the biases over land and over ocean do not impact each other.« less

Model, Proxy and Isotopic Perspectives on the East African Humid Period

NASA Technical Reports Server (NTRS)

Tierney, Jessica E.; Lewis, Sophie C.; Cook, Benjamin I.; LeGrande, Allegra N.; Schmidt, Gavin A.

2011-01-01

Both North and East Africa experienced more humid conditions during the early and mid-Holocene epoch (11,000-5000yr BP; 11-5 ka) relative to today. The North African Humid Period has been a major focus of paleoclimatic study, and represents a response of the hydrological cycle to the increase in boreal summer insolation and associated ocean, atmosphere and land surface feedbacks. Meanwhile, the mechanisms that caused the coeval East African Humid Period are poorly understood. Here, we use results from isotopeenabled coupled climate modeling experiments to investigate the cause of the East African Humid Period. The modeling results are interpreted alongside proxy records of both water balance and the isotopic composition of rainfall. Our simulations show that the orbitally-induced increase in dry season precipitation and the subsequent reduction in precipitation seasonality can explain the East African Humid Period, and this scenario agrees well with regional lake level and pollen paleoclimate data. Changes in zonal moisture flux from both the Atlantic and Indian Ocean account for the simulated increase in precipitation from June through November. Isotopic paleoclimate data and simulated changes in moisture source demonstrate that the western East African Rift Valley in particular experienced more humid conditions due to the influx of Atlantic moisture and enhanced convergence along the Congo Air Boundary. Our study demonstrates that zonal changes in moisture advection are an important determinant of climate variability in the East African region.

Variations of Sea Surface Temperature, Wind Stress, and Rainfall over the Tropical Atlantic and South America.

NASA Astrophysics Data System (ADS)

Nobre, Paulo; Srukla, J.

1996-10-01

Empirical orthogonal functions (E0Fs) and composite analyses are used to investigate the development of sea surface temperature (SST) anomaly patterns over the tropical Atlantic. The evolution of large-scale rainfall anomaly patterns over the equatorial Atlantic and South America are also investigated. 71e EOF analyses revealed that a pattern of anomalous SST and wind stress asymmetric relative to the equator is the dominant mode of interannual and longer variability over the tropical Atlantic. The most important findings of this study are as follows.Atmospheric circulation anomalies precede the development of basinwide anomalous SST patterns over the tropical Atlantic. Anomalous SST originate off the African coast simultaneously with atmospheric circulation anomalies and expand westward afterward. The time lag between wind stress relaxation (strengthening) and maximum SST warming (cooling) is about two months.Anomalous atmospheric circulation patterns over northern tropical Atlantic are phase locked to the seasonal cycle. Composite fields of SLP and wind stress over northern tropical Atlantic can be distinguished from random only within a few months preceding the March-May (MAM) season. Observational evidence is presented to show that the El Niño-Southern Oscillation phenomenon in the Pacific influences atmospheric circulation and SST anomalies over northern tropical Atlantic through atmospheric teleconnection patterns into higher latitudes of the Northern Hemisphere.The well-known droughts over northeastern Brazil (Nordeste) are a local manifestation of a much larger-scale rainfall anomaly pattern encompassing the whole equatorial Atlantic and Amazon region. Negative rainfall anomalies to the south of the equator during MAM, which is the rainy season for the Nordeste region, are related to an early withdrawal of the intertropical convergence zone toward the warm SST anomalies over the northern tropical Atlantic. Also, it is shown that precipitation anomalies over southern and northern parts of the Nordeste are out of phase: drought years over the northern Nordeste are commonly preceded by wetter years over the southern Nordeste, and vice versa.

Vema-TRANSIT - An interdisciplinary study on the bathymetry of the Vema-Fracture Zone and Puerto Rico Trench as well as abyssal Atlantic biodiversity

NASA Astrophysics Data System (ADS)

Riehl, Torben; Kaiser, Stefanie; Brandt, Angelika

2018-02-01

The seafloor below 3500 m remains largely unexplored. The paucity of knowledge of abyssal and hadal environments encompasses a wide spectrum of geological and biological patterns and processes as well as their interactions. Historically most marine research has been conducted in the North Atlantic. However, the high proportion of undescribed taxa frequently discovered at greater depth there underline the need to fill in these knowledge gaps. The Vema-TRANSIT campaign in northern winter 2014-2015 surveyed and sampled along almost the entire extent of one of the major offsets of the Mid-Atlantic Ridge (MAR), the Vema Fracture Zone (VFZ), as well as the deepest trench in the Atlantic, the Puerto Rico Trench (PRT). The discoveries that were made include new data on deep-sea habitats showing geologically complex features across all crust ages from 110 Ma until present. Moreover, some new species and genera of the abyssal and hadal benthos were described herein. Not only the taxa themselves, but also their distributions and genetic structure were elucidated. In this context, significant differences in abundances, community composition, and species distribution were detected that were affected by the MAR as well as by the depth transition between hadal PRT and the adjacent abyss. Despite significant differences between eastern and western communities, the MAR does not represent an absolute barrier. Instead, the VFZ, and especially the VTF may serve as a connecting feature between east and west and this may be exemplary for fracture zones across the whole Atlantic. Nevertheless, the MAR as well as the 3000-m-depth gradient between abyss and hadal appear to restrict gene flow for poor dispersers and thus contribute to speciation processes in the deep sea.

Causes and Consequences of Exceptional North Atlantic Heat Loss in Recent Winters

NASA Astrophysics Data System (ADS)

Josey, Simon; Grist, Jeremy; Duchez, Aurelie; Frajka-Williams, Eleanor; Hirschi, Joel; Marsh, Robert; Sinha, Bablu

2016-04-01

The mid-high latitude North Atlantic loses large amounts of heat to the atmosphere in winter leading to dense water formation. An examination of reanalysis datasets (ERA-Interim, NCEP/NCAR) reveals that heat loss in the recent winters 2013-14 and 2014-15 was exceptionally strong. The causes and consequences of this extraordinary ocean heat loss will be discussed. In 2013-2014, the net air-sea heat flux anomaly averaged over the whole winter exceeded 100 Wm-2 in the eastern subpolar gyre (the most extreme in the period since 1979 spanned by ERA-Interim). The causes of this extreme heat loss will be shown to be severe latent and sensible heat fluxes driven primarily by anomalously strong westerly airflows from North America and northerly airflows originating in the Nordic Seas. The associated sea level pressure anomaly field reflects the dominance of the second mode of atmospheric variability, the East Atlantic Pattern (EAP) over the North Atlantic Oscillation (NAO) in this winter. The extreme winter heat loss had a significant impact on the ocean extending from the sea surface into the deeper layers and a re-emergent cold Sea Surface Temperature (SST) anomaly is evident in November 2014. The following winter 2014-15 experienced further extreme heat loss that served to amplify the strength of the re-emergent SST anomaly. By summer 2015, an unprecedented cold mid-latitude North Atlantic Ocean surface temperature anomaly is evident in observations and has been widely referred to as the 'big blue blob'. The role played by the extreme surface heat loss in the preceding winters in generating this feature and it subsequent evolution through winter 2015-16 will be explored.

Determine precipitation rates from visible and infrared satellite images of clouds by pattern recognition technique. Progress Report, 1 Jul. 1985 - 31 Mar. 1987 Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Weinman, James A.; Garan, Louis

1987-01-01

A more advanced cloud pattern analysis algorithm was subsequently developed to take the shape and brightness of the various clouds into account in a manner that is more consistent with the human analyst's perception of GOES cloud imagery. The results of that classification scheme were compared with precipitation probabilities observed from ships of opportunity off the U.S. east coast to derive empirical regressions between cloud types and precipitation probability. The cloud morphology was then quantitatively and objectively used to map precipitation probabilities during two winter months during which severe cold air outbreaks were observed over the northwest Atlantic. Precipitation probabilities associated with various cloud types are summarized. Maps of precipitation probability derived from the cloud morphology analysis program for two months and the precipitation probability derived from thirty years of ship observation were observed.

Identifying Important Atlantic Areas for the conservation of Balearic shearwaters: Spatial overlap with conservation areas

NASA Astrophysics Data System (ADS)

Pérez-Roda, Amparo; Delord, Karine; Boué, Amélie; Arcos, José Manuel; García, David; Micol, Thierry; Weimerskirch, Henri; Pinaud, David; Louzao, Maite

2017-07-01

Marine protected areas (MPAs) are considered one of the main tools in both fisheries and conservation management to protect threatened species and their habitats around the globe. However, MPAs are underrepresented in marine environments compared to terrestrial environments. Within this context, we studied the Atlantic non-breeding distribution of the southern population of Balearic shearwaters (Puffinus mauretanicus) breeding in Eivissa during the 2011-2012 period based on global location sensing (GLS) devices. Our objectives were (1) to identify overall Important Atlantic Areas (IAAs) from a southern population, (2) to describe spatio-temporal patterns of oceanographic habitat use, and (3) to assess whether existing conservation areas (Natura 2000 sites and marine Important Bird Areas (IBAs)) cover the main IAAs of Balearic shearwaters. Our results highlighted that the Atlantic staging (from June to October in 2011) dynamic of the southern population was driven by individual segregation at both spatial and temporal scales. Individuals ranged in the North-East Atlantic over four main IAAs (Bay of Biscay: BoB, Western Iberian shelf: WIS, Gulf of Cadiz: GoC, West of Morocco: WoM). While most individuals spent more time on the WIS or in the GoC, a small number of birds visited IAAs at the extremes of their Atlantic distribution range (i.e., BoB and WoM). The chronology of the arrivals to the IAAs showed a latitudinal gradient with northern areas reached earlier during the Atlantic staging. The IAAs coincided with the most productive areas (higher chlorophyll a values) in the NE Atlantic between July and October. The spatial overlap between IAAs and conservation areas was higher for Natura 2000 sites than marine IBAs (areas with and without legal protection, respectively). Concerning the use of these areas, a slightly higher proportion of estimated positions fell within marine IBAs compared to designated Natura 2000 sites, with Spanish and Portuguese conservation areas being the most visited. Our results support the current design of conservation areas in Spain and Portugal regarding the protection of adult breeders of this highly mobile species.

Biogeography of Anurans from the Poorly Known and Threatened Coastal Sandplains of Eastern Brazil.

PubMed

Xavier, Ariane Lima; Guedes, Thaís Barreto; Napoli, Marcelo Felgueiras

2015-01-01

The east coast of Brazil comprises an extensive area inserted in the Tropical Atlantic Domain and is represented by sandy plains of beach ridges commonly known as Restingas. The coastal environments are unique and house a rich amphibian fauna, the geographical distribution patterns of which are incipient. Biogeographical studies can explain the current distributional patterns and provide the identification of natural biogeographical units. These areas are important in elucidating the evolutionary history of the taxa and the areas where they occur. The aim of this study was to seek natural biogeographical units in the Brazilian sandy plains of beach ridges by means of distribution data of amphibians and to test the main predictions of the vicariance model to explain the patterns found. We revised and georeferenced data on the geographical distribution of 63 anuran species. We performed a search for latitudinal distribution patterns along the sandy coastal plains of Brazil using the non-metric multidimensional scaling method (NMDS) and the biotic element analysis to identify natural biogeographical units. The results showed a monotonic variation in anuran species composition along the latitudinal gradient with a break in the clinal pattern from 23°S to 25°S latitude (states of Rio de Janeiro to São Paulo). The major predictions of the vicariance model were corroborated by the detection of four biotic elements with significantly clustered distribution and by the presence of congeneric species distributed in distinct biotic elements. The results support the hypothesis that vicariance could be one of the factors responsible for the distribution patterns of the anuran communities along the sandy coastal plains of eastern Brazil. The results of the clusters are also congruent with the predictions of paleoclimatic models made for the Last Glacial Maximum of the Pleistocene, such as the presence of historical forest refugia and biogeographical patterns already detected for amphibians in the Atlantic Rainforest.

Biogeography of Anurans from the Poorly Known and Threatened Coastal Sandplains of Eastern Brazil

PubMed Central

Xavier, Ariane Lima; Guedes, Thaís Barreto; Napoli, Marcelo Felgueiras

2015-01-01

The east coast of Brazil comprises an extensive area inserted in the Tropical Atlantic Domain and is represented by sandy plains of beach ridges commonly known as Restingas. The coastal environments are unique and house a rich amphibian fauna, the geographical distribution patterns of which are incipient. Biogeographical studies can explain the current distributional patterns and provide the identification of natural biogeographical units. These areas are important in elucidating the evolutionary history of the taxa and the areas where they occur. The aim of this study was to seek natural biogeographical units in the Brazilian sandy plains of beach ridges by means of distribution data of amphibians and to test the main predictions of the vicariance model to explain the patterns found. We revised and georeferenced data on the geographical distribution of 63 anuran species. We performed a search for latitudinal distribution patterns along the sandy coastal plains of Brazil using the non-metric multidimensional scaling method (NMDS) and the biotic element analysis to identify natural biogeographical units. The results showed a monotonic variation in anuran species composition along the latitudinal gradient with a break in the clinal pattern from 23°S to 25°S latitude (states of Rio de Janeiro to São Paulo). The major predictions of the vicariance model were corroborated by the detection of four biotic elements with significantly clustered distribution and by the presence of congeneric species distributed in distinct biotic elements. The results support the hypothesis that vicariance could be one of the factors responsible for the distribution patterns of the anuran communities along the sandy coastal plains of eastern Brazil. The results of the clusters are also congruent with the predictions of paleoclimatic models made for the Last Glacial Maximum of the Pleistocene, such as the presence of historical forest refugia and biogeographical patterns already detected for amphibians in the Atlantic Rainforest. PMID:26047484

Impact of the Dominant Large-scale Teleconnections on Winter Temperature Variability over East Asia

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Kim, Hae-Dong

2013-01-01

Monthly mean geopotential height for the past 33 DJF seasons archived in Modern Era Retrospective analysis for Research and Applications reanalysis is decomposed into the large-scale teleconnection patterns to explain their impacts on winter temperature variability over East Asia. Following Arctic Oscillation (AO) that explains the largest variance, East Atlantic/West Russia (EA/WR), West Pacific (WP) and El Nino-Southern Oscillation (ENSO) are identified as the first four leading modes that significantly explain East Asian winter temperature variation. While the northern part of East Asia north of 50N is prevailed by AO and EA/WR impacts, temperature in the midlatitudes (30N-50N), which include Mongolia, northeastern China, Shandong area, Korea, and Japan, is influenced by combined effect of the four leading teleconnections. ENSO impact on average over 33 winters is relatively weaker than the impact of the other three teleconnections. WP impact, which has received less attention than ENSO in earlier studies, characterizes winter temperatures over Korea, Japan, and central to southern China region south of 30N mainly by advective process from the Pacific. Upper level wave activity fluxes reveal that, for the AO case, the height and circulation anomalies affecting midlatitude East Asian winter temperature is mainly located at higher latitudes north of East Asia. Distribution of the fluxes also explains that the stationary wave train associated with EA/WR propagates southeastward from the western Russia, affecting the East Asian winter temperature. Investigation on the impact of each teleconnection for the selected years reveals that the most dominant teleconnection over East Asia is not the same at all years, indicating a great deal of interannual variability. Comparison in temperature anomaly distributions between observation and temperature anomaly constructed using the combined effect of four leading teleconnections clearly show a reasonable consistency between them, demonstrating that the seasonal winter temperature distributions over East Asia are substantially explained by these four large-scale circulation impacts.

76 FR 3596 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-20

.... 0907151138-1011-02] RIN 0648-AY03 Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto Rico and the U.S. Virgin Islands; Queen Conch Management Measures AGENCY: National... includes Lang Bank east of St. Croix, U.S. Virgin Islands (USVI), when harvest and possession of queen...

75 FR 61133 - Marine Mammals and Endangered Species; File Nos. 808-1735, 14233, 14506, 14603, and 14726

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-04

... comparative studies. Llewellyn Ehrhart, Ph.D. [File No. 14506], University of Central Florida, P.O. Box 162368... research on North Atlantic right whales had been submitted by the Provincetown Center for Coastal Studies... study North Atlantic right whales along the U.S. East Coast from Florida to Maine via aerial and vessel...

Comparison of the Impact of the Arctic Oscillation and East Atlantic - West Russia Teleconnection on Interannual Variation in East Asian Winter Temperatures and Monsoon

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Kim, Hae-Dong

2014-01-01

The large-scale impacts of the Arctic Oscillation (AO) and the East Atlantic/West Russia (EA/WR) teleconnection on the East Asian winter climate anomalies are compared for the past 34 winters focusing on 1) interannual monthly to seasonal temperature variability, 2) East Asian winter monsoon (EAWM), and 3) the Siberian high (SH) and cold surge. Regression analysis reveals warming by AO and EA/WR over mid-latitude East Asia during their positive phase and vice versa. The EA/WR impact is found to be comparable to the AO impact in affecting the East Asian temperature and monsoon. For example, warm (cold) months over mid-latitude East Asia during the positive (negative) AO are clearly seen when the AO and EA/WR are in the same phase. Near zero correlation is found between temperature and the AO phase when both teleconnections are in an opposite phase. The well-known negative relationship between SH and the AO phase is observed significantly more often when the AO is in the same phase with the EA/WR. Also, the indices of EAWM, cold surge, and SH are found to be more highly negative-correlated with the EA/WR rather than with the AO. The advective temperature change and associated circulation demonstrate that the anomalous large-scale field including the SH over the mid-latitude Asian inland is better represented by the EA/WR, influencing the East Asian winter climates. These results suggest that the impact of EA/WR should be considered more important than previously thought for a better understanding of East Asian winter temperature and monsoon variability.

Climate projections of spatial variations in coastal storm surges along the Gulf of Mexico and U.S. east coast

NASA Astrophysics Data System (ADS)

Yao, Zhigang; Xue, Zuo; He, Ruoying; Bao, Xianwen; Xie, Jun; Ge, Qian

2017-02-01

Using statistically downscaled atmospheric forcing, we performed a numerical investigation to evaluate future climate's impact on storm surges along the Gulf of Mexico and U.S. east coast. The focus is on the impact of climatic changes in wind pattern and surface pressure while neglecting sea level rise and other factors. We adapted the regional ocean model system (ROMS) to the study region with a mesh grid size of 7-10 km in horizontal and 18 vertical layers. The model was validated by a hindcast of the coastal sea levels in the winter of 2008. Model's robustness was confirmed by the good agreement between model-simulated and observed sea levels at 37 tidal gages. Two 10-year forecasts, one for the IPCC Pre-Industry (PI) and the other for the A1FI scenario, were conducted. The differences in model-simulated surge heights under the two climate scenarios were analyzed. We identified three types of responses in extreme surge heights to future climate: a clear decrease in Middle Atlantic Bight, an increase in the western Gulf of Mexico, and non-significant response for the remaining area. Such spatial pattern is also consistent with previous projections of sea surface winds and ocean wave heights.

Sources of iron and phosphate affect the distribution of diazotrophs in the North Atlantic

NASA Astrophysics Data System (ADS)

Ratten, Jenni-Marie; LaRoche, Julie; Desai, Dhwani K.; Shelley, Rachel U.; Landing, William M.; Boyle, Ed; Cutter, Gregory A.; Langlois, Rebecca J.

2015-06-01

Biological nitrogen fixation (BNF) supplies nutrient-depleted oceanic surface waters with new biologically available fixed nitrogen. Diazotrophs are the only organisms that can fix dinitrogen, but the factors controlling their distribution patterns in the ocean are not well understood. In this study, the relative abundances of eight diazotrophic phylotypes in the subtropical North Atlantic Ocean were determined by quantitative PCR (qPCR) of the nifH gene using TaqMan probes. A total of 152 samples were collected at 27 stations during two GEOTRACES cruises; Lisbon, Portugal to Mindelo, Cape Verde Islands (USGT10) and Woods Hole, MA, USA via the Bermuda Time Series (BATS) to Praia, Cape Verde Islands (USGT11). Seven of the eight diazotrophic phylotypes tested were detected. These included free-living and symbiotic cyanobacteria (unicellular groups (UCYN) A, B and C, Trichodesmium, the diatom-associated cyanobacteria Rhizoselinia-Richelia and Hemiaulus-Richelia) and a γ-proteobacterium (Gamma A, AY896371). The nifH gene abundances were analyzed in the context of a large set of hydrographic parameters, macronutrient and trace metal concentrations measured in parallel with DNA samples using the PRIMER-E software. The environmental variables that most influenced the abundances and distribution of the diazotrophic phylotypes were determined. We observed a geographic segregation of diazotrophic phylotypes between east and west, with UCYN A, UCYN B and UCYN C and the Rhizosolenia-Richelia symbiont associated with the eastern North Atlantic (east of 40°W), and Trichodesmium and Gamma A detected across the basin. Hemiaulus-Richelia symbionts were primarily found in temperate waters near the North American coast. The highest diazotrophic phylotype abundance and diversity were associated with temperatures greater than 22 °C in the surface mixed layer, a high supply of iron from North African aeolian mineral dust deposition and from remineralized nutrients upwelled at the edge of the oxygen minimum zone off the northwestern coast of Africa.

Large and giant hydrocarbon accumulations in the transitional continent-ocean zone

NASA Astrophysics Data System (ADS)

Khain, V. E.; Polyakova, I. D.

2008-05-01

The petroleum resource potential is considered for the Atlantic, West Pacific, and East Pacific types of deepwater continental margins. The most considerable energy resources are concentrated at the Atlantic-type passive margins in the zone transitional to the ocean. The less studied continental slope of backarc seas of the generally active margins of the West Pacific type is currently not so rich in discoveries as the Atlantic-type margin, but is not devoid of certain expectations. In some of their parameters, the margins bounded by continental slopes may be regarded as analogs of classical passive margins. At the margins of the East Pacific type, the petroleum potential is solely confined to transform segments. In the shelf-continental-slope basins of the rift and pull-apart nature, petroleum fields occur largely in the upper fan complex, and to a lesser extent in the lower graben (rift) complex. In light of world experience, the shelf-continental-slope basins of the Arctic and Pacific margins of Russia are evaluated as highly promising.

A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds.

USGS Publications Warehouse

Pearce-Higgins, James W.; Brown, Daniel J.; Douglas, David J.T.; Alves, José A.; Bellio, Mariagrazia; Bocher, Pierrick; Buchannan, Graeme M.; Clay, Robert P.; Conklin, Jesse R.; Crockford, Nicola; Dann, Peter; Elts, Jaanus; Friis, Christian; Fuller, Richard A.; Gill, Jennifer A.; Gosbell, Ken; Johnson, James A.; Marquez-Ferrando, Rocio; Masero, José A.; Melville, David S.; Millington, Spike; Minton, Clive; Mundkur, Taej; Nol, Erika; Pehlak, Hannes; Piersma, Theunis; Rogers, Danny I.; Ruthrauff, Daniel R.; Senner, Nathan R.; Nazeer Shah, Junid; Sheldon, Rob D.; Soloviev, Sergej A.; Tomkovich, Pavel S.; Verkuil, Yvonne I.

2017-01-01

The Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian- Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species' recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species.

The long-term variability of Changma in the East Asian summer monsoon system: A review and revisit

NASA Astrophysics Data System (ADS)

Lee, June-Yi; Kwon, MinHo; Yun, Kyung-Sook; Min, Seung-Ki; Park, In-Hong; Ham, Yoo-Geun; Jin, Emilia Kyung; Kim, Joo-Hong; Seo, Kyong-Hwan; Kim, WonMoo; Yim, So-Young; Yoon, Jin-Ho

2017-05-01

Changma, which is a vital part of East Asian summer monsoon (EASM) system, plays a critical role in modulating water and energy cycles in Korea. Better understanding of its long-term variability and change is therefore a matter of scientific and societal importance. It has been indicated that characteristics of Changma have undergone significant interdecadal changes in association with the mid-1970s global-scale climate shift and the mid-1990s EASM shift. This paper reviews and revisits the characteristics on the long-term changes of Changma focusing on the underlying mechanisms for the changes. The four important features are manifested mainly during the last few decades: 1) mean and extreme rainfalls during Changma period from June to September have been increased with the amplification of diurnal cycle of rainfall, 2) the dry spell between the first and second rainy periods has become shorter, 3) the rainfall amount as well as the number of rainy days during August have significantly increased, probably due to the increase in typhoon landfalls, and 4) the relationship between the Changma rainfall and Western Pacific Subtropical High on interannual time scale has been enhanced. The typhoon contribution to the increase in heavy rainfall is attributable to enhanced interaction between typhoons and midlatitude baroclinic environment. It is noted that the change in the relationship between Changma and the tropical sea surface temperature (SST) over the Indian, Pacific, and Atlantic Oceans is a key factor in the long-term changes of Changma and EASM. Possible sources for the recent mid-1990s change include 1) the tropical dipole-like SST pattern between the central Pacific and Indo-Pacific region (the global warming hiatus pattern), 2) the recent intensification of tropical SST gradients among the Indian Ocean, the western Pacific, and the eastern Pacific, and 3) the tropical Atlantic SST warming.

The Role of the North Atlantic Oscillation (NAO) on Recent Greenland Surface Mass Loss and Mass Partitioning

NASA Astrophysics Data System (ADS)

Tedesco, M.; Alexander, P.; Porter, D. F.; Fettweis, X.; Luthcke, S. B.; Mote, T. L.; Rennermalm, A.; Hanna, E.

2017-12-01

Despite recent changes in Greenland surface mass losses and atmospheric circulation over the Arctic, little attention has been given to the potential role of large-scale atmospheric processes on the spatial and temporal variability of mass loss and partitioning of the GrIS mass loss. Using a combination of satellite gravimetry measurements, outputs of the MAR regional climate model and reanalysis data, we show that changes in atmospheric patterns since 2013 over the North Atlantic region of the Arctic (NAA) modulate total mass loss trends over Greenland together with the spatial and temporal distribution of mass loss partitioning. For example, during the 2002 - 2012 period, melting persistently increased, especially along the west coast, as a consequence of increased insulation and negative NAO conditions characterizing that period. Starting in 2013, runoff along the west coast decreased while snowfall increased substantially, when NAO turned to a more neutral/positive state. Modeled surface mass balance terms since 1950 indicate that part of the GRACE-period, specifically the period between 2002 and 2012, was exceptional in terms of snowfall over the east and northeast regions. During that period snowfall trend decreased to almost 0 Gt/yr from a long-term increasing trend, which presumed again in 2013. To identify the potential impact of atmospheric patterns on mass balance and its partitioning, we studied the spatial and temporal correlations between NAO and snowfall/runoff. Our results indicate that the correlation between summer snowfall and NAO is not stable during the 1950 - 2015 period. We further looked at changes in patterns of circulation using self organizing maps (SOMs) to identify the atmospheric patterns characterizing snowfall during different periods. We discuss potential implications for past changes and future GCM and RCM simulations.

The sensitivity of snowfall to weather states over Sweden

NASA Astrophysics Data System (ADS)

Norin, Lars; Devasthale, Abhay; L'Ecuyer, Tristan S.

2017-09-01

For a high-latitude country like Sweden snowfall is an important contributor to the regional water cycle. Furthermore, snowfall impacts surface properties, affects atmospheric thermodynamics, has implications for traffic and logistics management, disaster preparedness, and also impacts climate through changes in surface albedo and turbulent heat fluxes. For Sweden it has been shown that large-scale atmospheric circulation patterns, or weather states, are important for precipitation variability. Although the link between atmospheric circulation patterns and precipitation has been investigated for rainfall there are no studies focused on the sensitivity of snowfall to weather states over Sweden.In this work we investigate the response of snowfall to eight selected weather states. These weather states consist of four dominant wind directions together with cyclonic and anticyclonic circulation patterns and enhanced positive and negative phases of the North Atlantic Oscillation. The presented analysis is based on multiple data sources, such as ground-based radar measurements, satellite observations, spatially interpolated in situ observations, and reanalysis data. The data from these sources converge to underline the sensitivity of falling snow over Sweden to the different weather states.In this paper we examine both average snowfall intensities and snowfall accumulations associated with the different weather states. It is shown that, even though the heaviest snowfall intensities occur during conditions with winds from the south-west, the largest contribution to snowfall accumulation arrives with winds from the south-east. Large differences in snowfall due to variations in the North Atlantic Oscillation are shown as well as a strong effect of cyclonic and anticyclonic circulation patterns. Satellite observations are used to reveal the vertical structures of snowfall during the different weather states.

Role of Tropical Atlantic SST Variability as a Modulator of El Nino Teleconnections

NASA Technical Reports Server (NTRS)

Ham, Yoo-Geun; Sung, Mi-Kyung; An, Soon-II; Schubert, Siegfried D.; Kug, Jong-Seong

2014-01-01

The present study suggests that the off-equatorial North Atlantic (NATL) SST warming plays a significant role in modulating El Niño teleconnection and its impact on the North Atlantic and European regions. The El Niño events accompanied by NATL SST warming exhibit south-north dipole pattern over the Western Europe to Atlantic, while the ENSO teleconnection pattern without NATL warming exhibits a Rossby wave-like pattern confined over the North Pacific and western Atlantic. Especially, the El Niño events with NATL warming show positive (negative) geopotential-height anomalies over the North Atlantic (Western Europe) which resemble the negative phase of the NAO. Consistently, it is shown using a simple statistical model that NATL SSTA in addition to the tropical Pacific SSTA leads to better prediction on regional climate variation over the North Atlantic and European regions. This role of NATL SST on ENSO teleconnection is also validated and discussed in a long term simulation of coupled global circulation model (CGCM).

Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Nakamura, Jennifer

This study explores seasonal patterns and structures of moisture transport pathways from the North Atlantic Ocean and the Gulf of Mexico that lead to extreme large-scale precipitation and floods over land. Storm tracks, such as the tropical cyclone tracks in the Northern Atlantic Ocean, are an example of moisture transport pathways. In the first part, North Atlantic cyclone tracks are clustered by the moments to identify common traits in genesis locations, track shapes, intensities, life spans, landfalls, seasonal patterns, and trends. The clustering results of part one show the dynamical behavior differences of tropical cyclones born in different parts of the basin. Drawing on these conclusions, in the second part, statistical track segment model is developed for simulation of tracks to improve reliability of tropical cyclone risk probabilities. Moisture transport pathways from the North Atlantic Ocean are also explored though the specific regional flood dynamics of the U.S. Midwest and the United Kingdom in part three of the dissertation. Part I. Classifying North Atlantic Tropical Cyclones Tracks by Mass Moments. A new method for classifying tropical cyclones or similar features is introduced. The cyclone track is considered as an open spatial curve, with the wind speed or power information along the curve considered as a mass attribute. The first and second moments of the resulting object are computed and then used to classify the historical tracks using standard clustering algorithms. Mass moments allow the whole track shape, length and location to be incorporated into the clustering methodology. Tropical cyclones in the North Atlantic basin are clustered with K-means by mass moments producing an optimum of six clusters with differing genesis locations, track shapes, intensities, life spans, landfalls, seasonality, and trends. Even variables that are not directly clustered show distinct separation between clusters. A trend analysis confirms recent conclusions of increasing tropical cyclones in the basin over the past two decades. However, the trends vary across clusters. Part II: Tropical cyclone Intensity and Track Simulator (HITS) with Atlantic Ocean Applications for Risk Assessment. A nonparametric stochastic model is developed and tested for the simulation of tropical cyclone tracks. Tropical cyclone tracks demonstrate continuity and memory over many time and space steps. Clusters of tracks can be coherent, and the separation between clusters may be marked by geographical locations where groups of tracks diverge due to the physics of the underlying process. Consequently, their evolution may be non-Markovian. Markovian simulation models, as often used, may produce tracks that potentially diverge or lose memory quicker than nature. This is addressed here through a model that simulates tracks by randomly sampling track segments of varying length, selected from historical tracks. For performance evaluation, a spatial grid is imposed on the domain of interest. For each grid box, long-term tropical cyclone risk is assessed through the annual probability distributions of the number of storm hours, landfalls, winds, and other statistics. Total storm length is determined at birth by local distribution, and movement to other tropical cyclone segments by distance to neighbor tracks, comparative vector, and age of track. An assessment of the performance for tropical cyclone track simulation and potential directions for the improvement and use of such model are discussed. Part III: Dynamical Structure of Extreme Floods in the U.S. Midwest and the United Kingdom. Twenty extreme spring floods that occurred in the Ohio Basin between 1901 and 2008, identified from daily river discharge data, are investigated and compared to the April 2011 Ohio River flood event. Composites of synoptic fields for the flood events show that all these floods are associated with a similar pattern of sustained advection of low-level moisture and warm air from the tropical Atlantic Ocean and the Gulf of Mexico. The typical flow conditions are governed by an anomalous semi-stationary ridge situated east of the US East Coast, which steers the moisture and converges it into the Ohio Valley. Significantly, the moisture path common to all the 20 cases studied here as well as the case of April 2011 is distinctly different from the normal path of Atlantic moisture during spring, which occurs further west. It is shown further that the Ohio basin moisture convergence responsible for the floods is caused primarily by the atmospheric circulation anomaly advecting the climatological mean moisture field. Transport and related convergence due to the covariance between moisture anomalies and circulation anomalies are of secondary but non-negligible importance. The importance of atmospheric circulation anomalies to floods is confirmed by conducting a similar analysis for a series of winter floods on the River Eden in northwest England.

Outlook for coastal plain forests: a subregional report from the Southern Forest Futures Project

Treesearch

Kier Klepzig; Richard Shelfer; Zanethia Choice

2014-01-01

The U.S. Coastal Plain consists of seven sections: the Northern Atlantic, Eastern Atlantic, Peninsular Florida, Southern Gulf, Middle Gulf-East, Middle Gulf-West, and Western Gulf. It covers a large area, consists of a diverse array of habitats, and supports a diverse array of uses. This report presents forecasts from the Southern Forest Futures Project that are...

75 FR 8819 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-26

.... 040205043-4043-01] RIN 0648-XU38 Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Reopening of the Gulf Group King Mackerel East Coast Subzone AGENCY..., little tunny, and, in the Gulf of Mexico only, dolphin and bluefish) is managed under the Fishery...

50 CFR 600.105 - Intercouncil boundaries.

Code of Federal Regulations, 2014 CFR

2014-10-01

... intersection point of Connecticut, Rhode Island, and New York at 41°18′16.249″ N. lat. and 71°54′28.477″ W. long. and proceeds south 37°22′32.75″ East to the point of intersection with the outward boundary of the EEZ as specified in the Magnuson-Stevens Act. (b) Mid-Atlantic and South Atlantic Councils. The...

50 CFR 600.105 - Intercouncil boundaries.

Code of Federal Regulations, 2013 CFR

2013-10-01

... intersection point of Connecticut, Rhode Island, and New York at 41°18′16.249″ N. lat. and 71°54′28.477″ W. long. and proceeds south 37°22′32.75″ East to the point of intersection with the outward boundary of the EEZ as specified in the Magnuson-Stevens Act. (b) Mid-Atlantic and South Atlantic Councils. The...

50 CFR 600.105 - Intercouncil boundaries.

Code of Federal Regulations, 2011 CFR

2011-10-01

... intersection point of Connecticut, Rhode Island, and New York at 41°18′16.249″ N. lat. and 71°54′28.477″ W. long. and proceeds south 37°22′32.75″ East to the point of intersection with the outward boundary of the EEZ as specified in the Magnuson-Stevens Act. (b) Mid-Atlantic and South Atlantic Councils. The...

50 CFR 600.105 - Intercouncil boundaries.

Code of Federal Regulations, 2012 CFR

2012-10-01

... intersection point of Connecticut, Rhode Island, and New York at 41°18′16.249″ N. lat. and 71°54′28.477″ W. long. and proceeds south 37°22′32.75″ East to the point of intersection with the outward boundary of the EEZ as specified in the Magnuson-Stevens Act. (b) Mid-Atlantic and South Atlantic Councils. The...

South Atlantic intermediate water advances into the North-east Atlantic with reduced Atlantic meridional overturning circulation during the last glacial period

NASA Astrophysics Data System (ADS)

Dubois-Dauphin, Quentin; Bonneau, Lucile; Colin, Christophe; Montero-Serrano, Jean-Carlos; Montagna, Paolo; Blamart, Dominique; Hebbeln, Dierk; Van Rooij, David; Pons-Branchu, Edwige; Hemsing, Freya; Wefing, Anne-Marie; Frank, Norbert

2016-06-01

The Nd isotopic composition (ɛNd) of seawater and cold-water coral (CWC) samples from the Gulf of Cádiz and the Alboran Sea, at a depth of 280-827 m were investigated in order to constrain middepth water mass dynamics within the Gulf of Cádiz over the past 40 ka. ɛNd of glacial and Holocene CWC from the Alboran Sea and the northern Gulf of Cádiz reveals relatively constant values (-8.6 to -9.0 and -9.5 to -10.4, respectively). Such values are similar to those of the surrounding present-day middepth waters from the Mediterranean Outflow Water (MOW; ɛNd ˜ -9.4) and Mediterranean Sea Water (MSW; ɛNd ˜ -9.9). In contrast, glacial ɛNd values for CWC collected at thermocline depth (550-827 m) in the southern Gulf of Cádiz display a higher average value (-8.9 ± 0.4) compared to the present-day value (-11.7 ± 0.3). This implies a higher relative contribution of water masses of Mediterranean (MSW) or South Atlantic origin (East Antarctic Intermediate Water, EAAIW). Our study has produced the first evidence of significant radiogenic ɛNd values (˜ -8) at 19, 23-24, and 27 ka, which are coeval with increasing iceberg discharges and a weakening of Atlantic Meridional Overturning Circulation (AMOC). Since MOW ɛNd values remained stable during the last glacial period, it is suggested that these radiogenic ɛNd values most likely reflect an enhanced northward propagation of glacial EAAIW into the eastern Atlantic Basin.

Thermal ecotypes of amphi-Atlantic algae. I. Algae of Arctic to cold-temperate distribution ( Chaetomorpha melagonium, Devaleraea ramentacea and Phycodrys rubens)

NASA Astrophysics Data System (ADS)

Novaczek, I.; Lubbers, G. W.; Breeman, A. M.

1990-09-01

Three species of Arctic to cold-temperate amphi-Atlantic algae, all occurring also in the North Pacific, were tested for growth and/or survival at temperatures of -20 to 30°C. When isolates from both western and eastern Atlantic shores were tested side-by-side, it was found that thermal ecotypes may occur in such Arctic algae. Chaetomorpha melagonium was the most eurythermal of the 3 species. Isolates of this alga were alike in temperature tolerance and growth rate but Icelandic plants were more sensitive to the lethal temperature of 25°C than were more southerly isolates from both east and west. With regard to Devaleraea ramentacea, one Canadian isolate grew extraordinarily well at -2 and 0°C, and all tolerated temperatures 2 3°C higher than the lethal limit (18 20°C) of isolates from Europe. Concerning Phycodrys rubens, both eastern and western isolates died at 20°C but European plants tolerated the lethal high temperature longer, were more sensitive to freezing, and attained more rapid growth at optimal temperatures. The intertidal species, C. melagonium and D. ramentacea, both survived freezing at -5 and -20°C, at least for short time periods. C. melagonium was more susceptible than D. ramentacea to desiccation. Patterns of thermal tolerance may provide insight into the evolutionary history of seaweed species.

Quantitative Estimation of the Impact of European Teleconnections on Interannual Variation of East Asian Winter Temperature and Monsoon

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Kim, Hae-Dong

2014-01-01

The impact of European teleconnections including the East AtlanticWest Russia (EA-WR), the Scandinavia (SCA), and the East Atlantic (EA) on East Asian winter temperature variability was quantified and compared with the combined effect of the Arctic Oscillation (AO), the Western Pacific (WP), and the El-Nino Southern Oscillation (ENSO), which are originated in the Northern Hemispheric high-latitudes or the Pacific. Three European teleconnections explained 22-25 percent of the total monthly upper-tropospheric height variance over Eurasia. Regression analysis revealed warming by EA-WR and EA and cooling by SCA over mid-latitude East Asia during their positive phase and vice versa. Temperature anomalies were largely explained by the advective temperature change process at the lower troposphere. The average spatial correlation over East Asia (90-180E, 10-80N) for the last 34 winters between observed and reconstructed temperature comprised of AO, WP and ENSO effect (AWE) was approximately 0.55, and adding the European teleconnection components (ESE) to the reconstructed temperature improved the correlation up to approximately 0.64. Lower level atmospheric structure demonstrated that approximately five of the last 34 winters were significantly better explained by ESE than AWE to determine East Asian seasonal winter temperatures. We also compared the impact between EA-WR and AO on the 1) East Asian winter monsoon, 2) cold surge, and 3) the Siberian high. These three were strongly coupled, and their spatial features and interannual variation were somewhat better explained by EA-WR than AO. Results suggest that the EA-WR impact must be treated more importantly than previously thought for a better understanding of East Asian winter temperature and monsoon variability.

Emerging European winter precipitation pattern linked to atmospheric circulation changes over the North Atlantic region in recent decades

NASA Astrophysics Data System (ADS)

Ummenhofer, Caroline C.; Seo, Hyodae; Kwon, Young-Oh; Parfitt, Rhys; Brands, Swen; Joyce, Terrence M.

2017-08-01

Dominant European winter precipitation patterns over the past century, along with their associated extratropical North Atlantic circulation changes, are evaluated using cluster analysis. Contrary to the four regimes traditionally identified based on daily wintertime atmospheric circulation patterns, five distinct seasonal precipitation regimes are detected here. Recurrent precipitation patterns in each regime are linked to changes in atmospheric blocking, storm track, and sea surface temperatures across the North Atlantic region. Multidecadal variability in the frequency of the precipitation patterns reveals more (fewer) winters with wet conditions in northern (southern) Europe in recent decades and an emerging distinct pattern of enhanced wintertime precipitation over the northern British Isles. This pattern has become unusually common since the 1980s and is associated with changes in moisture transport and more frequent atmospheric river events. The observed precipitation changes post-1950 coincide with changes in storm track activity over the central/eastern North Atlantic toward the northern British Isles.

Geochemical and Rheological Constraints on the Dynamics of the Oceanic Upper Mantle

DTIC Science & Technology

2007-09-01

405-412. 201 Dick, H. J. B., Natland, J., Party, L. . S., 1994. Melt transport and evolution in the shallow mantle beneath the East Pacific Rise ...in the shallow mantle beneath the East Pacific Rise . In: M6vel, C., Gillis, K. M., Allan, J. F., Meyer, P. S. (Eds.), Proceedings of the Ocean...according to ridge location: East Pacific Rise (EPR), Mid-Cayman Rise (MCR), Central Indian Ridge/Carlsberg Ridge (CIR/Carl), Mid-Atlantic Ridge (MAR

The Influence of Ridge Geometry at the Ultraslow-Spreading Southwest Indiean Ridge (9 deg - 25 deg E): Basalt Composition Sensitivity to Variations in Source and Process

DTIC Science & Technology

2006-02-01

East Pacific Rise , 5 degrees 30’-14 degrees 30’ N , Natures, 322, 422-429. Langmuir, C. H., E. M. Klein, and T. Plank (1992...Mantle source heterogeneity and melting processes beneath seafloor spreading centers: The East Pacific Rise , 18 degrees -19 degrees S, Journal of... East Pacific Rise , Aumento, F., and H. Loubat, The Mid-Atlantic Ridge Near Proc. Ocean Drill. Program Sci. Results, 147, 103-134,

The U.S. East Coast Meteotsunami of June 13, 2013

NASA Astrophysics Data System (ADS)

Knight, W. R.; Whitmore, P.; Kim, Y.; Wang, D.; Becker, N. C.; Weinstein, S.; Walker, K.

2013-12-01

NOAA's two Tsunami Warning Centers (TWCs) provide advance notification to coastal communities concerning tsunami hazards. While the focus is primarily on seismic sources, the U.S. East Coast event of June 13, 2013 indicates the importance of understanding and forecasting atmospherically-driven tsunamis, or meteotsunamis, as well. Here we describe an approach which explains the generation of this event by atmospheric processes, and suggests that the causative forces can be monitored and used to forecast meteotsunami occurrence. The U.S. East Coast tsunami of June 13, 2013 was well recorded at tide gauges from North Carolina to Massachusetts as well as at Bermuda and Puerto Rico. It also triggered DART 44402, just east of the Atlantic shelf break at 39.4N. As there was no seismic energy release associated with the tsunami and an eastward propagating major weather system crossed the Atlantic coast just before the tsunami, the focus turned to atmospheric forcing. Tsunami forecast models used at the two U.S. TWCs were modified to introduce moving atmospheric pressure distributions as sources. In a simple case, a north-south oriented line air pressure jump of width 50 km and pressure of 4 mb at sea level was moved eastward at 20 m/s. The speed matched both the storm speed at the coast and the long wave speed for 40 m deep water, thus allowing for resonant coupling of atmosphere to ocean in the shelf region (Proudman Resonance). Considering the simplicity of the source, a reasonable comparison between the modeled and observed tsunami was obtained with regards to arrival time and height. The proposed source also offers an explanation of the later wave arrivals at US tide gauges. These typically lagged the arrival at Bermuda - a location much further east. This pattern can be explained within the context of Proudman resonance if the waves arriving at coastal stations originated at the shelf break as reflected waves. Model animations of wave dynamics corroborate this phenomenon. The contribution of edge waves generated as the system moves over the coast is also examined. Remaining questions include the importance of shelf parameters in setting the wave fetch and the 'Q' of Proudman resonance along the Atlantic coastline. In other words, are some stretches of shelf more conducive to tsunami formation than others? Wind stress was disregarded in the initial modeling work leaving its possible importance as another unanswered question. Operational questions include how to detect likely meteotsunami conditions with real-time meteorological measurements, and what form alerts should take. The minimum necessary temporal resolution of the pressure sensors along with their density and siting needs to be determined. Because details of the source, such as direction and speed of propagation, will likely subject unique sections of coastline to tsunami attack, the detailed analysis of data from sensor arrays to be used in forecasting will be important.

Late Quaternary surface circulation in the east equatorial South Atlantic: Evidence from Alkenone sea surface temperatures

NASA Astrophysics Data System (ADS)

Schneider, Ralph R.; Müller, Peter J.; Ruhland, GöTz

1995-04-01

Angola Basin and Walvis Ridge records of past sea surface temperatures (SST) derived from the alkenone Uk37 index are used to reconstruct the surface circulation in the east equatorial South Atlantic for the last 200,000 years. Comparison of SST estimates from surface sediments between 5° and 20°S with modern SST data suggests that the alkenone temperatures represent annual mean values of the surface mixed layer. Alkenone-derived temperatures for the warm climatic maxima of the Holocene and the penultimate interglacial are 1 to 4°C higher than latest Holocene values. All records show glacial to interglacial differences of about 3.5°C in annual mean SST, which is about 1.5°C greater than the difference estimated by CLIMAP (1981) for the eastern Angola Basin. At the Walvis Ridge, significant SST variance is observed at all of the Earth's orbital periodicities. SST records from the Angola Basin vary predominantly at 23- and 100-kyr periodicities. For the precessional cycle, SST changes at the Walvis Ridge correspond to variations of boreal summer insolation over Africa and lead ice volume changes, suggesting that the east equatorial South Atlantic is sensitive to African monsoon intensity via trade-wind zonality. Angola Basin SST records lag those from the Walvis Ridge and the equatorial Atlantic by about 3 kyr. The comparison of Angola Basin and Walvis Ridge SST records implies that the Angola-Benguela Front (ABF) (currently at about 14-16°S) has remained fairly stationary between 12° and 20°S (the limits of our cores) during the last two glacial-interglacial cycles. The temperature contrast associated with the ABF exhibits a periodic 23-kyr variability which is coherent with changes in boreal summer insolation over Africa. These observations suggest that surface waters north of the present ABF have not directly responded to monsoon-modulated changes in the trade-wind vector, that the central field of zonally directed trades in the southern hemisphere was not shifted or extended northward by several degrees of latitude during glacials, and that a cyclonic gyre circulation has existed in the east equatorial South Atlantic over the last 200,000 years. This scenario contradicts former assumptions of glacial intensification of the Benguela Current into the eastern Angola Basin and increased coastal upwelling off Angola.

Episodes of subsidence and uplift of the conjugate margins of Greenland and Norway after opening of the NE Atlantic

NASA Astrophysics Data System (ADS)

Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Chalmers, James A.

2015-04-01

We have undertaken a regional study of the thermo-­tectonic development of East Greenland (68-75°N) and of southern Norway (58-64°N). We take advantage of the general observation that that the effects of uplift often are reflected more clearly onshore than offshore, and of the specific condition that the mountains of southern East Greenland expose thick basalts that were extruded onto a largely horizontal lava plain near sea level during breakup of the NE Atlantic at the Paleocene-Eocene transition. It is thus clear that the present-­day elevation of these basalts up to 3.7 km a.s.l. were reached after breakup. Our results based on apatite fission-­track analysis (AFTA) data from East Greenland reveal a long history of post-­Palaeozoic burial and exhumation across the region and show that the terrains of Palaeozoic and older rocks were buried below a 2-3 km­-thick cover prior to a series of Mesozoic events of uplift and exhumation. The AFTA results from southern Norway reveal events of Mesozoic uplift and exhumation that are broadly simultaneous with those in Greenland. Volcanic and sedimentary rocks accumulated on the subsiding, East Greenland margin during and following breakup and then began to be exhumed during late Eocene uplift that preceded a major, early Oligocene plate reorganization in the NE Atlantic. The Norwegian margin also experienced Eocene subsidence and burial. Our AFTA data from southern Norway show evidence of an event of mid­Cenozoic uplift and exhumation that overlap with the early Oligocene onset of progradation of clastic wedges towards the south and with the formation of a major, late Eocene unconformity along the NW European margin. The uplift event at the Eocene-Oligocene transition that affected wide areas in the NE Atlantic domain was followed by two regional events of uplift and incision of the East Greenland margin in the late Miocene and Pliocene whereas the Neogene uplift of southern Norway began in the early Miocene and was followed by the Pliocene phase that also affected East Greenland. In East Greenland, the end-­result of the three events of Cenozoic uplift and exhumation are two elevated erosion surfaces of Palaeogene and Neogene age. In southern Norway, a similar stepped landscape (the Palaeic relief) is also of Cenozoic age. In Greenland, definition of the chronology of events benefits from the availability of AFTA data from boreholes onshore where the plateau surfaces truncate Palaeogene basalts, and thus make it possible to date these surfaces and correlate them with offshore unconformities. In Norway, these factors are lacking, but the overall similarity of the onshore landscapes and Cenozoic cooling history and of the offshore sedimentary section to those in Greenland, suggests that the landscapes along these conjugate margins developed in similar fashion. This implies that the mountains of Norway also reached their present elevation in the late Cenozoic, long after Atlantic breakup.

Florida

Atmospheric Science Data Center

2014-05-15

... eastern (Atlantic) coast, partially obscured by clouds, are Palm Beach, Fort Lauderdale, and Miami. Further to the east, the shallow waters ... MISR category:  gallery date:  Oct 18, 2000 Images:  Florida ...

On international fisheries agreements, entry deterrence, and ecological uncertainty.

PubMed

Ellefsen, Hans; Grønbæk, Lone; Ravn-Jonsen, Lars

2017-05-15

A prerequisite for an international fisheries agreement (IFA) to be stable is that parties expect the benefits from joining the agreement to exceed the benefits from free riding on the agreement, and parties only comply with the agreement as long as this is true. The agreement, therefore, implicitly builds on an expectation of the ecological condition of the natural resource. Game theoretical models often assume that all parties have the same (often perfect) information about the resource and that the exploitation is an equilibrium use of the stock. As stated by experts in natural science, the fish ecology still has many open questions, for example how to predict population dynamics, migration patterns, food availability, etc. In some cases, parties disagree about the state, abundance, and migration of a stock, which can reduce the possibilities of reaching an agreement for exploitation of the stock. This paper develops a model and applies it to the North-East Atlantic mackerel fishery, in order to analyze an IFA under different ecological scenarios, and also combines the model with the economic theory of entry deterrence. The model is used empirically to determine whether the parties with original access to the resource have an advantage when forming an agreement with a new party in having the ability to fish the stock down to a smaller size and thereby prevent another party from entering into the fishery. With a basis in entry deterrence, combined with lack of information, the paper illustrates the obstacles that have made an agreement for the North-East Atlantic mackerel so difficult to achieve. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metazoan parasites in the head region of the bullet tuna Auxis rochei (Osteichthyes: Scombridae) from the western Mediterranean Sea.

PubMed

Mele, S; Saber, S; Gómez-Vives, M J; Garippa, G; Alemany, F; Macías, D; Merella, P

2015-11-01

The head region of 72 bullet tuna Auxis rochei from the western Mediterranean Sea (south-east Spain and the Strait of Gibraltar) was examined for parasites. Seven metazoan species were found in the fish from south-east Spain: three monogeneans, two trematodes and two copepods, whereas only three species were isolated in the fish from the Strait of Gibraltar. A comparison of the levels of infection of the parasites according to fish size in south-east Spain showed that the prevalence of Didymozoon auxis and the mean abundance of Allopseudaxine macrova were higher in the larger hosts (range of fork length = 38-44 cm) than in the smaller ones (33-37 cm). A comparison of the parasite infections according to geographical region showed that the mean abundances of Nematobothriinae gen. sp. and Caligus bonito were higher in fish from south-east Spain than in those from the Strait of Gibraltar. A comparison of the parasite fauna of A. rochei from the Mediterranean Sea with the published data on Auxis spp. from the Atlantic, Indian and Pacific Oceans revealed the closest similarity between the Mediterranean A. rochei and the Atlantic A. thazard.

Spatial patterns of trends and teleconnections in climate indices relevant for Mexican maize

NASA Astrophysics Data System (ADS)

Dewes, C. F.

2013-05-01

This study contributes to the discussion of climate trends in Mexico and the influence of hemispheric-scale variability patterns over the period 1950-2008. Its uniqueness is three-fold. First, the choice of climate indices under scrutiny aims to represent an agro-climatic perspective, geared towards maize in particular because of the major role this crop plays in Mexico's culture, diet, and economy. Second, the spatial resolution and coverage of these findings can be useful for interpretations at the local level (i.e. district or state), yet keeping the broad national picture in perspective. This should be particularly useful to agro-climate forecasting, assessment of impacts, and/or policy development. Third, this study uncovers a dominance of the North Atlantic over the Pacific Ocean in respect to remote influences on trend patterns in Mexico. Trends in precipitation show that east of the central highlands, the rainy season is starting later and becoming drier. The same is occurring along the Pacific coastal plain, but there an increase in extreme events is also observed. For south-central Mexico and the Yucatán, rains not only are starting earlier but intensity and frequency of extreme events are also increasing. In some of these areas dry days are becoming more frequent. Trends in temperature suggest that highlands are warming at faster rates than lowlands, which in some places are actually cooling. Warming in the fall-winter growing season is more pronounced than in the spring-summer growing season. On the other hand, cold spells during mid-summer are becoming more frequent over the highlands. Connections were found between these trends and large-scale variability patterns, namely El Niño Southern Oscillation (ENSO), Pacific North America (PNA), the North Atlantic Oscillation (NAO), and Caribbean sea surface temperatures (SSTs). Interannual variability related to ENSO and the PNA, and trends towards more Niño-like conditions, are associated with increasing precipitation over the Yucatán and a few areas along the southern Pacific coast, and with more dry days - though accompanied by stronger extreme precipitation events - over southwestern Mexico. They are also associated with a delaying start of the rainy season in a narrow area just east of the south-central highlands and higher risk of frost during late-winter up in the highlands. Increasing Caribbean SSTs are associated with increasing temperatures over the mainland and stronger precipitation over the Yucatán. Variability in the NAO and its trend towards more positive phases is associated the drying trend in central Mexico, intensification of precipitation over the northwest, and also increasing temperatures over the entire mainland in both the warm and cold growing seasons. The atmospheric circulation over the Atlantic Ocean and its increasing tropical SSTs, have a larger and broader participation in Mexican trends than is noted with the Pacific counterparts.

Large-Scale Aerosol Modeling and Analysis

DTIC Science & Technology

2007-09-30

deserts of the world: Arabian Gulf, Sea of Japan, China Sea , Mediterranean Sea , and the Tropical Atlantic Ocean. NAAPS also accurately predicts the...fate of large-scale smoke and pollution plumes. With its global and continuous coverage, 1 Report Documentation Page Form ApprovedOMB No. 0704-0188...origin of dust plumes impacting naval operations in the Red Sea , Mediterranean, eastern Atlantic, Gulf of Guinea, Sea of Japan, Yellow Sea , and East

50 CFR 648.10 - VMS and DAS requirements for vessel owners/operators.

Code of Federal Regulations, 2014 CFR

2014-10-01

...′ 22. A point in eastern Vineyard Sound 41°30′ 70°33′ 24. A point east of Martha's Vineyard 41°22.2′ 70... vessel issued an Areas 2/3 open access herring permit, or a vessel declaring an Atlantic herring carrier... declare an Atlantic herring carrier trip via VMS must notify NMFS by declaring a herring trip with the...

Diversity of late Neogene Monachinae (Carnivora, Phocidae) from the North Atlantic, with the description of two new species

PubMed Central

Peredo, Carlos Mauricio; Meyvisch, Pjotr; Louwye, Stephen

2018-01-01

While the diversity of ‘southern seals’, or Monachinae, in the North Atlantic realm is currently limited to the Mediterranean monk seal, Monachus monachus, their diversity was much higher during the late Miocene and Pliocene. Although the fossil record of Monachinae from the North Atlantic is mainly composed of isolated specimens, many taxa have been erected on the basis of fragmentary and incomparable specimens. The humerus is commonly considered the most diagnostic postcranial bone. The research presented in this study limits the selection of type specimens for different fossil Monachinae to humeri and questions fossil taxa that have other types of bones as type specimens, such as for Terranectes parvus. In addition, it is essential that the humeri selected as type specimens are (almost) complete. This questions the validity of partial humeri selected as type specimens, such as for Terranectes magnus. This study revises Callophoca obscura, Homiphoca capensis and Pliophoca etrusca, all purportedly known from the Lee Creek Mine, Aurora, North Carolina, in addition to their respective type localities in Belgium, South Africa and Italy, respectively. C. obscura is retained as a monachine seal taxon that lived both on the east coast of North America and in the North Sea Basin. However, H. capensis from North America cannot be identified beyond the genus level, and specimens previously assigned to Pl. etrusca from North America clearly belong to different taxa. Indeed, we also present new material and describe two new genera of late Miocene and Pliocene Monachinae from the east coast of North America: Auroraphoca atlantica nov. gen. et nov. sp., and Virginiaphoca magurai nov. gen. et nov. sp. This suggests less faunal interchange of late Neogene Monachinae between the east and west coasts of the North Atlantic than previously expected. PMID:29657825

A Satellite View of a Back-door Cold Front

NASA Image and Video Library

2014-05-29

A "backdoor cold front" is bringing April temperatures to the U.S. northeast and Mid-Atlantic today, May 29. The backdoor cold front brings relief to the Mid-Atlantic after temperatures in Washington, D.C. hit 92F on Tuesday, May 27 and 88F on Wednesday, May 28 at Reagan National Airport, according to the National Weather Service (NWS). NWS forecasters expect the high temperature for May 29 to only reach 60F in the District of Columbia. NOAA's GOES-East satellite captured a view of the clouds associated with the backdoor cold front that stretch from southern Illinois to North Carolina. The National Weather Service forecast expects the backdoor cold front to bring showers to the Midwest, Northeast, and Mid-Atlantic today, May 29. According to the National Oceanic and Atmospheric Administration, a backdoor cold front is a cold front moving south or southwest along the Atlantic seaboard and Great Lakes; these are especially common during the spring months. This visible image was taken by NOAA's GOES-East satellite on May 29 at 12:30 UTC (8:30 a.m. EDT). The image was created at NASA/NOAA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland. In addition to the backdoor cold front clouds, the GOES-East image shows clouds circling around a low pressure area located in eastern Texas. That low pressure area is expected to bring rain from Texas eastward over the southeastern U.S. According to NOAA's National Weather Service, the slow-moving low pressure area in the Deep South "will bring heavy showers and thunderstorms from Louisiana to Alabama through Thursday. This area is already saturated from previous rainfall, so flash flooding will be possible." Image: NASA/NOAA GOES Project Caption: NASA Goddard/Rob Gutro

Relative impacts of insolation changes, meltwater fluxes and ice sheets on African and Asian monsoons during the Holocene

NASA Astrophysics Data System (ADS)

Marzin, Charline; Braconnot, Pascale; Kageyama, Masa

2013-11-01

In order to better understand the evolution of the Afro-Asian monsoon in the early Holocene, we investigate the impact on boreal summer monsoon characteristics of (1) a freshwater flux in the North Atlantic from the surrounding melting ice sheets and (2) a remnant ice sheet over North America and Europe. Sensitivity experiments run with the IPSL_CM4 model show that both the meltwater flux and the remnant ice sheets induce a cooling of similar amplitude of the North Atlantic leading to a southward shift of the Inter-Tropical Convergence Zone over the tropical Atlantic and to a reduction of the African monsoon. The two perturbations have different impacts in the Asian sector. The meltwater flux results in a weakening of the Indian monsoon and no change in the East Asian monsoon, whereas the remnant ice sheets induce a strengthening of the Indian monsoon and a strong weakening of the East Asian monsoon. Despite the similar coolings in the Atlantic Ocean, the ocean heat transport is reduced only in the meltwater flux experiment, which induces slight differences between the two experiments in the role of the surface latent heat flux in the tropical energetics. In the meltwater experiment, the southward shift of the subtropical jet acts to cool the upper atmosphere over the Tibetan Plateau and hence to weaken the Indian monsoon. In the ice sheet experiment this effect is overwhelmed by the changes in extratropical stationary waves induced by the ice sheets, which are associated with a larger cooling over the Eurasian continent than in the meltwater experiment. However these sensitivity experiments suggest that insolation is the dominant factor explaining the relative changes of the African, Indian and East Asian monsoons from the early to the mid-Holocene.

Diversity of late Neogene Monachinae (Carnivora, Phocidae) from the North Atlantic, with the description of two new species

NASA Astrophysics Data System (ADS)

Dewaele, Leonard; Peredo, Carlos Mauricio; Meyvisch, Pjotr; Louwye, Stephen

2018-03-01

While the diversity of `southern seals', or Monachinae, in the North Atlantic realm is currently limited to the Mediterranean monk seal, Monachus monachus, their diversity was much higher during the late Miocene and Pliocene. Although the fossil record of Monachinae from the North Atlantic is mainly composed of isolated specimens, many taxa have been erected on the basis of fragmentary and incomparable specimens. The humerus is commonly considered the most diagnostic postcranial bone. The research presented in this study limits the selection of type specimens for different fossil Monachinae to humeri and questions fossil taxa that have other types of bones as type specimens, such as for Terranectes parvus. In addition, it is essential that the humeri selected as type specimens are (almost) complete. This questions the validity of partial humeri selected as type specimens, such as for Terranectes magnus. This study revises Callophoca obscura, Homiphoca capensis and Pliophoca etrusca, all purportedly known from the Lee Creek Mine, Aurora, North Carolina, in addition to their respective type localities in Belgium, South Africa and Italy, respectively. C. obscura is retained as a monachine seal taxon that lived both on the east coast of North America and in the North Sea Basin. However, H. capensis from North America cannot be identified beyond the genus level, and specimens previously assigned to Pl. etrusca from North America clearly belong to different taxa. Indeed, we also present new material and describe two new genera of late Miocene and Pliocene Monachinae from the east coast of North America: Auroraphoca atlantica nov. gen. et nov. sp., and Virginiaphoca magurai nov. gen. et nov. sp. This suggests less faunal interchange of late Neogene Monachinae between the east and west coasts of the North Atlantic than previously expected.

Penetration of Atlantic Walker Circulation Into East Africa During Early to mid-Holocene: Hydrogen Isotope Evidence From Sacred Lake, Mt. Kenya

NASA Astrophysics Data System (ADS)

Hou, J.; Russell, J. M.; Huang, Y.

2007-12-01

The tropics play a very important role in global climate variability, yet the mechanisms behind the tropical climate variation remain poorly understood. Here, we present a high-resolution, well-dated record from Sacred Lake, Kenya, East Africa. We measured D/H ratios of botryococcenes, a class of highly specific biomarkers produced by freshwater algae ( Botrycoccus braunii) in a sediment core obtained from this open lake. Our main goal is to examine changes in East African rainfall amount and moisture source during the past 18kyr BP. During the late Pleistocene and late Holocene, the hydrogen isotope records track local hydrological variations inferred from numerous lake level and pollen records from the region. However, during the early to mid-Holocene (10-5ka cal yr BP), the D/H values from Sacred Lake were as much as 90 per mil heavier than during the late Pleistocene and late Holocene. If the "amount effect" is the main control on the isotopic compositions of rainfall during the early to mid Holocene, Our data would suggest drier conditions, which is inconsistent with the "African Humid Period" inferred by numerous records of the mid-Holocene. We propose that the high isotopic ratios in precipitation in East Africa during the early to mid-Holocene is due to an eastward shift in the large-scale atmospheric circulation of the tropics. In East Africa, this shift involves a major increase in moisture source from the Atlantic Ocean relative to Indian Ocean. Heavier isotope ratios of precipitation originated from Atlantic Ocean result from the intensive convection and recycling of water vapor over the Congo Basin, as opposed to Indian moisture that traverses dry land masses and losses moisture rapidly. In comparison to the late Holocene, the early to mid-Holocene is characterized by relatively northerly positioning of the ITCZ and intense monsoon systems as well as weak ENSO. These factors combine to shift the walker circulation eastward, allowing the Atlantic moisture to penetrate farther into eastern Africa. Our theory is supported by climate model results, paleoclimate records from the Kilimanjaro ice core and Cariaco Basin, and other records from the Indian and Pacific Oceans. For example, the ice core in Kilimanjaro, East Africa suggest that the oxygen isotope ratios of precipitation were ~ 8 per mil higher during early to mid-Holocene than the late Holocene, which is consistent with our results.

Heat Flow and Hydrothermal Circulation of the Lucky Strike Segment, Mid Atlantic Ridge

NASA Astrophysics Data System (ADS)

Bonneville, A.; Escartin, J.; Lucazeau, F.; Cannat, M.; Gouze, P.; von Herzen, R. P.; Adam, C.; Le Bars, M.; Monoury, E.; Vidal, V.

2003-12-01

In June 2003, expedition Luckyflux aboard the R/V Poseidon conducted a heat flow survey of a zone centred on the Lucky Strike segment of the Mid Atlantic ridge south of the Azores between ˜35° N and 39° N. Using a 5 m-long lance with 7 outrigger thermal probes, about 150 successful thermal gradient measurements were obtained, 140 of these with in-situ thermal conductivity. Measurements were made at ˜1 mile intervals along several profiles, where adequately sedimented sites were identified using 6-channel and 3.5 kHz seismic data from the previous Sudazores'98 cruise. We conducted heat flow measurements in two areas: a near axis region within the V-shaped ridge of overthickened crust that emanated from the Azores hotspot between ˜14 and 4 Ma, and an off-axis region East of the V-shaped ridge. The off-axis region is characterized by an homogeneous sediment cover, 300-400 m thick, and crustal ages varying between ˜6 and >10 Ma. Long wavelength (tens of km) low heat flow anomalies can be identified but the mean of 160 mWm-2 is comparable to the conductive heat flow expected for a crust of that age. Along two 80-km profiles perpendicular to the ridge, we observed coherent but different patterns. On the first profile, low heat flow values of 20-50 mWm-2 are observed at the base of the V-shaped ridge. These values are 100 mWm-2 below the profile average, showing that hydrothermal circulations can also affect oceanic crust beneath a thick and relatively impermeable sediment cover. On the other profile, heat flow generally decreases from west to east. On both profiles, higher than average values of heat flow are also present, associated on one of them with a nearly outcropping basement elevation. These contrasting overall heat flow patterns in similar geological context indicate that the likely pattern of hydrothermal circulations is mainly 3D, and not driven only by the presence of basement outcrops. In the near-axis region, where the tectonic structure is more complicated and the sediment cover heterogeneous, heat flow data show no clear spatial variation and their mean value, 60 to 90 mWm-2, is systematically lower than theoretical conductive values for young seafloor. These heat flow differences will be used to estimate the importance of advection in the heat budget. This characterization of the regional thermal state around a slow-spreading segment will provide the basis for future long-term studies on the structure, thermal evolution and the hydrothermal systems within the MOMAR (MOnitoring the Mid Atlantic Ridge) project.

Dynamics of upwelling annual cycle in the equatorial Atlantic Ocean

NASA Astrophysics Data System (ADS)

Wang, Li-Chiao; Jin, Fei-Fei; Wu, Chau-Ron; Hsu, Huang-Hsiung

2017-04-01

The annual upwelling is an important component of the equatorial Atlantic annual cycle. A simple theory is proposed using the framework of Zebiak-Cane (ZC) ocean model for insights into the dynamics of the upwelling annual cycle. It is demonstrated that in the Atlantic equatorial region this upwelling is dominated by Ekman processing in the west, whereas in the east it is primarily owing to shoaling and deepening of the thermocline resulting from equatorial mass meridional recharge/discharge and zonal redistribution processes associated with wind-driven equatorial ocean waves. This wind-driven wave upwelling plays an important role in the development of the annual cycle in the sea surface temperature of the cold tongue in the eastern equatorial Atlantic.

Temporal patterns of phytoplankton abundance in the North Atlantic

NASA Technical Reports Server (NTRS)

Campbell, Janet W.

1989-01-01

A time series of CZCS images is being developed to study phytoplankton distribution patterns in the North Atlantic. The goal of this study is to observe temporal variability in phytoplankton pigments and other organic particulates, and to infer from these patterns the potential flux of biogenic materials from the euphotic layer to the deep ocean. Early results of this project are presented in this paper. Specifically, the satellite data used were 13 monthly composited images of CZCS data for the North Atlantic from January 1979 to January 1980. Results are presented for seasonal patterns along the 20 deg W meridian.

The role of clouds in driving North Atlantic multi-decadal climate variability in observations and models

NASA Astrophysics Data System (ADS)

Clement, A. C.; Bellomo, K.; Murphy, L.

2013-12-01

Large scale warming and cooling periods of the North Atlantic is known as the Atlantic Multidecadal Oscillation (AMO). The pattern of warming and cooling in the North Atlantic Ocean over the 20th century that has a characteristic spatial structure with maximum warming in the mid-latitudes and subtropics. This has been most often attributed to changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC), which in turn affects poleward heat transport. A recent modeling study by Booth et al. (2012), however, suggested that aerosols can explain both the spatial pattern and temporal history of Atlantic SST through indirect effects of aerosols on cloud cover; although this idea is controversial (Zhang et al., 2013). We have found observational evidence that changes in cloud amount can drive SST changes on multi-decadal timescale. We hypothesize that a positive local feedback between SST and cloud radiative effect amplifies SST and gives rise to the observed pattern of SST change. During cool North Atlantic periods, a southward shift of the ITCZ strengthens the trade winds in the tropical North Atlantic and increases low-level cloud cover, which acts to amplify the SST cooling in the North Atlantic. During warm periods in the North Atlantic, the opposite response occurs. We are testing whether the amplitude of this feedback is realistically simulated in the CMIP5 models, and whether inter-model differences in the amplitude of the feedback can explain differences in model simulations of Atlantic multi-decadal variability.

Sources of glacial moisture in Mesoamerica

USGS Publications Warehouse

Bradbury, J.P.

1997-01-01

Paleoclimatic records from Mesoamerica document the interplay between Atlantic and Pacific sources of precipitation during the last glacial stage and Holocene. Today, and throughout much of the Holocene, the entire region receives its principal moisture in the summer from an interaction of easterly trade winds with the equatorial calms. Glacial records from sites east of 95?? W in Guatemala, Florida, northern Venezuela and Colombia record dry conditions before 12 ka, however. West of 95?? W, glacial conditions were moister than in the Holocene. For example, pollen and diatom data show that Lake Pa??tzcuaro in the central Mexican highlands was cool, deep and fresh during this time and fossil pinyon needles in packrat middens in Chihuahua, Sonora, Arizona, and Texas indicate cooler glacial climates with increased winter precipitation. Cold Gulf of Mexico sea-surface temperatures and reduced strength of the equatorial calms can explain arid full and late glacial environments east of 95?? W whereas an intensified pattern of winter, westerly air flow dominated hydrologic balances as far south as 20?? N. Overall cooler temperatures may have increased effective moisture levels during dry summer months in both areas. ?? 1997 INQUA/ Elsevier Science Ltd.

Synoptic Scale North American Weather Tracks and the Formation of North Atlantic Windstorms

NASA Astrophysics Data System (ADS)

Baum, A. J.; Godek, M. L.

2014-12-01

Each winter, dozens of fatalities occur when intense North Atlantic windstorms impact Western Europe. Forecasting the tracks of these storms in the short term is often problematic, but long term forecasts provide an even greater challenge. Improved prediction necessitates the ability to identify these low pressure areas at formation and understand commonalities that distinguish these storms from other systems crossing the Atlantic, such as where they develop. There is some evidence that indicates the majority of intense windstorms that reach Europe have origins far west, as low pressure systems that develop over the North American continent. This project aims to identify the specific cyclogenesis regions in North America that produce a significantly greater number of dangerous storms. NOAA Ocean Prediction Center surface pressure reanalysis maps are used to examine the tracks of storms. Strong windstorms are characterized by those with a central pressure of less than 965 hPa at any point in their life cycle. Tracks are recorded using a coding system based on source region, storm track and dissipation region. The codes are analyzed to determine which region contains the most statistical significance with respect to strong Atlantic windstorm generation. The resultant set of codes also serves as a climatology of North Atlantic extratropical cyclones. Results indicate that a number of windstorms favor cyclogenesis regions off the east coast of the United States. A large number of strong storms that encounter east coast cyclogenesis zones originate in the central mountain region, around Colorado. These storms follow a path that exits North America around New England and subsequently travel along the Canadian coast. Some of these are then primed to become "bombs" over the open Atlantic Ocean.

Marine biodiversity in the Atlantic and Pacific coasts of South America: knowledge and gaps.

PubMed

Miloslavich, Patricia; Klein, Eduardo; Díaz, Juan M; Hernández, Cristián E; Bigatti, Gregorio; Campos, Lucia; Artigas, Felipe; Castillo, Julio; Penchaszadeh, Pablo E; Neill, Paula E; Carranza, Alvar; Retana, María V; Díaz de Astarloa, Juan M; Lewis, Mirtha; Yorio, Pablo; Piriz, María L; Rodríguez, Diego; Yoneshigue-Valentin, Yocie; Gamboa, Luiz; Martín, Alberto

2011-01-31

The marine areas of South America (SA) include almost 30,000 km of coastline and encompass three different oceanic domains--the Caribbean, the Pacific, and the Atlantic--ranging in latitude from 12∘N to 55∘S. The 10 countries that border these coasts have different research capabilities and taxonomic traditions that affect taxonomic knowledge. This paper analyzes the status of knowledge of marine biodiversity in five subregions along the Atlantic and Pacific coasts of South America (SA): the Tropical East Pacific, the Humboldt Current,the Patagonian Shelf, the Brazilian Shelves, and the Tropical West Atlantic, and it provides a review of ecosystem threats and regional marine conservation strategies. South American marine biodiversity is least well known in the tropical subregions (with the exception of Costa Rica and Panama). Differences in total biodiversity were observed between the Atlantic and Pacific oceans at the same latitude. In the north of the continent, the Tropical East Pacific is richer in species than the Tropical West Atlantic, however, when standardized by coastal length, there is very little difference among them. In the south, the Humboldt Current system is much richer than the Patagonian Shelf. An analysis of endemism shows that 75% of the species are reported within only one of the SA regions, while about 22% of the species of SA are not reported elsewhere in the world. National and regional initiatives focusing on new exploration, especially to unknown areas and ecosystems, as well as collaboration among countries are fundamental to achieving the goal of completing inventories of species diversity and distribution.These inventories will allow accurate interpretation of the biogeography of its two oceanic coasts and latitudinal trends,and will also provide relevant information for science based policies.

Hydrothermal sediments as a potential record of seawater Nd isotope compositions: The Rainbow vent site (36°14'N, Mid-Atlantic Ridge)

NASA Astrophysics Data System (ADS)

Chavagnac, ValéRie; Palmer, Martin R.; Milton, J. Andrew; Green, Darryl R. H.; German, Christopher R.

2006-09-01

Geochemical compositions and Sr and Nd isotopes were measured in two cores collected ˜2 and 5 km from the Rainbow hydrothermal vent site on the Mid-Atlantic Ridge. Overall, the cores record enrichments in Fe and other metals from hydrothermal fallout, but sequential dissolution of the sediments allows discrimination between a leach phase (easily leachable) and a residue phase (refractory). The oxy-anion and transition metal distribution combined with rare earth element (REE) patterns suggest that (1) the leach fraction is a mixture of biogenic carbonate and hydrothermal Fe-Mn oxy-hydroxide with no significant contribution from detrital material and (2) >99.5% of the REE content of the leach fraction is of seawater origin. In addition, the leach fraction has an average 87Sr/86Sr ratio indistinguishable from modern seawater at 0.70916. Although we lack the ɛNd value of present-day deep water at the Rainbow vent site, we believe that the REE budget of the leach fraction is predominantly of seawater origin. We suggest therefore that the leach fraction provides a record of local seawater ɛNd values. Nd isotope data from these cores span the period of 4-14 ka (14C ages) and yield ɛNd values for North East Atlantic Deep Water (NEADW) that are higher (-9.3 to -11.1) than those observed in the nearby Madeira Abyssal Plain from the same depth (-12.4 ± 0.9). This observation suggests that either the Iceland-Scotland Overflow Water (ISOW) and Lower Deep Water contributions to the formation of NEADW are higher along the Mid-Atlantic Ridge than in the surrounding basins or that the relative proportion of ISOW was higher during this period than is observed today. This study indicates that hydrothermal sediments have the potential to provide a higher-resolution record of deep water ɛNd values, and hence deepwater circulation patterns in the oceans, than is possible from other types of sediments.

Large-Scale Antecedent Conditions Associated with 2014-2015 Winter Onset over North America and mid-Winter Storminess Along the North Atlantic Coast

NASA Astrophysics Data System (ADS)

Bosart, L. F.; Papin, P. P.; Bentley, A. M.; Benjamin, M.; Winters, A. C.

2015-12-01

Winter 2014-2015 was marked by the coldest November weather in 35 years east of the Rockies and record-breaking snowstorms and cold from the eastern Great Lakes to Atlantic Canada in January and February 2015. Record-breaking warmth prevailed across the Intermountain West and Rockies beneath a persistent upper-level ridge. Winter began with a series of arctic air mass surges that culminated in an epic lake-effect snowstorm occurred over western New York before Thanksgiving and was followed by a series of snow and ice storms that disrupted Thanksgiving holiday travel widely. Winter briefly abated in part of December, but returned with a vengeance between mid-January and mid-February 2015 when multiple extreme weather events that featured record-breaking monthly and seasonal snowfalls and record-breaking daily minimum temperatures were observed. This presentation will show how: (1) the recurvature and extratropical transition (ET) of Supertyphoon (STY) Nuri in the western Pacific in early November 2014, and its subsequent explosive reintensification as an extratropical cyclone (EC), disrupted the North Pacific jet stream and downstream Northern Hemisphere (NH) circulation, produced high-latitude ridging and the formation of an omega block over western North America, triggered downstream baroclinic development and the formation of a deep trough over eastern North America, and ushered in winter 2014-2015, (2) the ET/EC of STY Nuri increased subsequent week two predictability over the North Pacific and North America in association with diabatically influenced high-latitude ridge building, and (3) the amplification of the large-scale NH flow pattern beginning in January 2015 resulted in the formation of persistent high-amplitude ridges over northeastern Russia, Alaska, western North America, and the North Atlantic while deep troughs formed over the eastern North Pacific and eastern North America. This persistent amplified flow pattern supported the occurrence of frequent heavy snowstorms, including blizzards, over parts of the northeastern United States and adjacent Atlantic Canada during the latter part of January and much of February 2015.

33 CFR 167.172 - Off Delaware Bay: Southeastern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.172 Off Delaware Bay: Southeastern...

33 CFR 167.172 - Off Delaware Bay: Southeastern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.172 Off Delaware Bay: Southeastern...

33 CFR 167.172 - Off Delaware Bay: Southeastern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.172 Off Delaware Bay: Southeastern...

33 CFR 167.172 - Off Delaware Bay: Southeastern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.172 Off Delaware Bay: Southeastern...

33 CFR 167.172 - Off Delaware Bay: Southeastern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.172 Off Delaware Bay: Southeastern...

76 FR 23907 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Queen Conch Fishery of Puerto...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

... Fishery of Puerto Rico and the U.S. Virgin Islands; Queen Conch Management Measures AGENCY: National... zone (EEZ) east of 64[deg]34' W. longitude, which includes Lang Bank east of St. Croix, U.S. Virgin... Enforcement Fairness Act of 1996 states that, for each rule or group of related rules for which an agency is...

Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Florida). WHITE MULLET.

DTIC Science & Technology

1985-05-01

of the head Class ............ .Osteichthyes length. Order .... .......... Perciformes - Family .... ........... Mugilidae REASON FOR INCLUSION IN...SERIES Geographic range: Atlantic and East- The white mullet, the second most ern Pacific; in the Western Atlantic common species of the family Mugilidae ...del ciclo de Rep. 55(34):1-15. vida de MugiI curema Valenciennes in Cuviere- Valenciennes, 1836 Moore, R. H. 1973. Energetic re- ilisces: Mugilidae

U.S. Navy Harbor Maintenance Dredging Atlas.

DTIC Science & Technology

1980-12-01

the ocean’s surf zone. Energy is so high that mud size (clay and silt) sediments are washed away leaving deposits of sand. Sand is rarely contaminated...Figure 11). Dredging is contracted for by the Atlantic Division, Naval Facilities Engineering Command (LANTNAVFACENGCOM). The hydraulically dredged spoil...by the Atlantic Ocean to the east and the St. Johns River on the north. The Mayport Naval Station is a major base, homeporting over 30 ships including

Linkages of Remote Sea Surface Temperatures and Atlantic Tropical Cyclone Activity Mediated by the African Monsoon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taraphdar, Sourav; Leung, Lai-Yung R.; Hagos, Samson M.

2015-01-28

Warm sea surface temperatures (SSTs) in North Atlantic and Mediterranean (NAMED) can influence tropical cyclone (TC) activity in the tropical East Atlantic by modulating summer convection over western Africa. Analysis of 30 years of observations show that the NAMED SST is linked to a strengthening of the Saharan heat low and enhancement of moisture and moist static energy in the lower atmosphere over West Africa, which favors a northward displacement of the monsoonal front. These processes also lead to a northward shift of the African easterly jet that introduces an anomalous positive vorticity from western Africa to the main developmentmore » region (50W–20E; 10N–20N) of Atlantic TC. By modulating multiple processes associated with the African monsoon, this study demonstrates that warm NAMED SST explains 8% of interannual variability of Atlantic TC frequency. Thus NAME SST may provide useful predictability for Atlantic TC activity on seasonal-to-interannual time scale.« less

MODIS Global Sea Surface Temperature

NASA Technical Reports Server (NTRS)

2002-01-01

Every day the Moderate-resolution Imaging Spectroradiometer (MODIS) measures sea surface temperature over the entire globe with high accuracy. This false-color image shows a one-month composite for May 2001. Red and yellow indicates warmer temperatures, green is an intermediate value, while blues and then purples are progressively colder values. The new MODIS sea surface temperature product will be particularly useful in studies of temperature anomalies, such as El Nino, as well as research into how air-sea interactions drive changes in weather and climate patterns. In the high resolution image, notice the amazing detail in some of the regional current patterns. For instance, notice the cold water currents that move from Antarctica northward along South America's west coast. These cold, deep waters upwell along an equatorial swath around and to the west of the Galapagos Islands. Note the warm, wide currents of the Gulf Stream moving up the United States' east coast, carrying Caribbean warmth toward Newfoundland and across the Atlantic toward Western Europe. Note the warm tongue of water extending from Africa's east coast to well south of the Cape of Good Hope. MODIS was launched in December 1999 aboard NASA's Terra satellite. For more details on this and other MODIS data products, please see NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Ocean Group, NASA GSFC, and the University of Miami

Large and local-scale influences on physical and chemical characteristics of coastal waters of Western Europe during winter

NASA Astrophysics Data System (ADS)

Tréguer, Paul; Goberville, Eric; Barrier, Nicolas; L'Helguen, Stéphane; Morin, Pascal; Bozec, Yann; Rimmelin-Maury, Peggy; Czamanski, Marie; Grossteffan, Emilie; Cariou, Thierry; Répécaud, Michel; Quéméner, Loic

2014-11-01

There is now a strong scientific consensus that coastal marine systems of Western Europe are highly sensitive to the combined effects of natural climate variability and anthropogenic climate change. However, it still remains challenging to assess the spatial and temporal scales at which climate influence operates. While large-scale hydro-climatic indices, such as the North Atlantic Oscillation (NAO) or the East Atlantic Pattern (EAP) and the weather regimes such as the Atlantic Ridge (AR), are known to be relevant predictors of physical processes, changes in coastal waters can also be related to local hydro-meteorological and geochemical forcing. Here, we study the temporal variability of physical and chemical characteristics of coastal waters located at about 48°N over the period 1998-2013 using (1) sea surface temperature, (2) sea surface salinity and (3) nutrient concentration observations for two coastal sites located at the outlet of the Bay of Brest and off Roscoff, (4) river discharges of the major tributaries close to these two sites and (5) regional and local precipitation data over the region of interest. Focusing on the winter months, we characterize the physical and chemical variability of these coastal waters and document changes in both precipitation and river runoffs. Our study reveals that variability in coastal waters is connected to the large-scale North Atlantic atmospheric circulation but is also partly explained by local river influences. Indeed, while the NAO is strongly related to changes in sea surface temperature at the Brest and Roscoff sites, the EAP and the AR have a major influence on precipitations, which in turn modulate river discharges that impact sea surface salinity at the scale of the two coastal stations.

Patterns of interannual climate variability in large marine ecosystems

NASA Astrophysics Data System (ADS)

Soares, Helena Cachanhuk; Gherardi, Douglas Francisco Marcolino; Pezzi, Luciano Ponzi; Kayano, Mary Toshie; Paes, Eduardo Tavares

2014-06-01

The purpose of this study is to investigate the vulnerability of the Brazilian and western African Large Marine Ecosystems (LMEs) to local and remote forcing, including the Pacific Decadal Oscillation (PDO) regime shift. The analyses are based on the total and partial correlation between climate indices (Niño3, tropical South Atlantic (TSA), tropical North Atlantic (TNA) and Antarctic oscillation (AAO) and oceanic and atmospheric variables (sea surface temperature (SST), wind stress, Ekman transport, sea level pressure and outgoing longwave radiation). Differences in the correlation fields between the cold and warm PDO indicate that this mode exerts a significant impact on the thermodynamic balance of the ocean-atmosphere system on the South Atlantic ocean, mainly in the South Brazil and Benguela LMEs. The PDO regime shift also resulted in an increase in the spatial variability of SST and wind stress anomalies, mainly along the western African LMEs. Another important finding is the strong AAO influence on the SST anomalies (SSTA) in the South Brazil LME. It is also striking that TSA modulates the relation between El Niño-Southern Oscillation (ENSO) and SSTA, by reducing the influence of ENSO on SSTA during the warm PDO period in the North and East Brazil LMEs and in the Guinea Current LME. The relation between AAO and SSTA on the tropical area is also influenced by the TSA. The results shown here give a clear indication that future ecosystem-based management actions aimed at the conservation of marine resources under climate change need to consider the high complexity of basin-scale interactions between local and remote climate forcings, including their effects on the ocean-atmosphere system of the South Atlantic ocean.

North Atlantic sub-decadal variability in climate models

NASA Astrophysics Data System (ADS)

Reintges, Annika; Martin, Thomas; Latif, Mojib; Park, Wonsun

2017-04-01

The North Atlantic Oscillation (NAO) is the dominant variability mode for the winter climate of the North Atlantic sector. During a positive (negative) NAO phase, the sea level pressure (SLP) difference between the subtropical Azores high and the subpolar Icelandic low is anomalously strong (weak). This affects, for example, temperature, precipitation, wind, and surface heat flux over the North Atlantic, and over large parts of Europe. In observations we find enhanced sub-decadal variability of the NAO index that goes along with a dipolar sea surface temperature (SST) pattern. The corresponding SLP and SST patterns are reproduced in a control experiment of the Kiel Climate Model (KCM). Large-scale air-sea interaction is suggested to be essential for the North Atlantic sub-decadal variability in the KCM. The Atlantic Meridional Overturning Circulation (AMOC) plays a key role, setting the timescale of the variability by providing a delayed negative feedback to the NAO. The interplay of the NAO and the AMOC on the sub-decadal timescale is further investigated in the CMIP5 model ensemble. For example, the average CMIP5 model AMOC pattern associated with sub-decadal variability is characterized by a deep-reaching dipolar structure, similar to the KCM's sub-decadal AMOC variability pattern. The results suggest that dynamical air-sea interactions are crucial to generate enhanced sub-decadal variability in the North Atlantic climate.

33 CFR 167.171 - Off Delaware Bay: Eastern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.171 Off Delaware Bay: Eastern approach...

33 CFR 167.174 - Off Delaware Bay: Precautionary area.

Code of Federal Regulations, 2012 CFR

2012-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.174 Off Delaware Bay: Precautionary area...

33 CFR 167.174 - Off Delaware Bay: Precautionary area.

Code of Federal Regulations, 2011 CFR

2011-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.174 Off Delaware Bay: Precautionary area...

33 CFR 167.171 - Off Delaware Bay: Eastern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.171 Off Delaware Bay: Eastern approach...

33 CFR 167.174 - Off Delaware Bay: Precautionary area.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.174 Off Delaware Bay: Precautionary area...

33 CFR 167.174 - Off Delaware Bay: Precautionary area.

Code of Federal Regulations, 2013 CFR

2013-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.174 Off Delaware Bay: Precautionary area...

33 CFR 167.171 - Off Delaware Bay: Eastern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.171 Off Delaware Bay: Eastern approach...

33 CFR 167.171 - Off Delaware Bay: Eastern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.171 Off Delaware Bay: Eastern approach...

33 CFR 167.171 - Off Delaware Bay: Eastern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.171 Off Delaware Bay: Eastern approach...

33 CFR 167.174 - Off Delaware Bay: Precautionary area.

Code of Federal Regulations, 2014 CFR

2014-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.174 Off Delaware Bay: Precautionary area...

Transportation Fuels Markets, PADD 1 and PADD 3

EIA Publications

2016-01-01

This study examines supply, consumption, and distribution of transportation fuels in Petroleum Administration for Defense Districts (PADDs) 1 and 3, or the U.S. East Coast and the Gulf Coast, respectively. The East Coast region includes states from Maine to Florida along the U.S. Atlantic Coast. The Gulf Coast region comprises states between New Mexico in the west to Alabama in the east along the Gulf of Mexico. For this study, transportation fuels include gasoline, diesel fuel and jet fuel. Residual fuel oil supply is also analyzed where applicable.

Millennial-scale northern Hemisphere Atlantic-Pacific climate teleconnections in the earliest Middle Pleistocene.

PubMed

Hyodo, Masayuki; Bradák, Balázs; Okada, Makoto; Katoh, Shigehiro; Kitaba, Ikuko; Dettman, David L; Hayashi, Hiroki; Kumazawa, Koyo; Hirose, Kotaro; Kazaoka, Osamu; Shikoku, Kizuku; Kitamura, Akihisa

2017-08-30

Suborbital-scale climate variations, possibly caused by solar activity, are observed in the Holocene and last-glacial climates. Recently published bicentennial-resolution paleoceanic environmental records reveal millennial-scale high-amplitude oscillations postdating the last geomagnetic reversal in the Marine Isotope Stage (MIS) 19 interglacial. These oscillations, together with decoupling of post-reversal warming from maximum sea-level highstand in mid-latitudes, are key features for understanding the climate system of MIS 19 and the following Middle Pleistocene. It is unclear whether the oscillations are synchronous, or have the same driver as Holocene cycles. Here we present a high resolution record of western North Pacific submarine anoxia and sea surface bioproductivity from the Chiba Section, central Japan. The record reveals many oxic events in MIS 19, coincident with cold intervals, or with combined cold and sea-level fall events. This allows detailed correlations with paleoceanic records from the mid-latitude North Atlantic and Osaka Bay, southwest Japan. We find that the millennial-scale oscillations are synchronous between East and West hemispheres. In addition, during the two warmest intervals, bioproductivity follows the same pattern of change modulated by bicentennial cycles that are possibly related to solar activity.

Determining the effect of key climate drivers on global hydropower production

NASA Astrophysics Data System (ADS)

Galelli, S.; Ng, J. Y.; Lee, D.; Block, P. J.

2017-12-01

Accounting for about 17% of total global electrical power production, hydropower is arguably the world's main renewable energy source and a key asset to meet Paris climate agreements. A key component of hydropower production is water availability, which depends on both precipitation and multiple drivers of climate variability acting at different spatial and temporal scales. To understand how these drivers impact global hydropower production, we study the relation between four patterns of ocean-atmosphere climate variability (i.e., El Niño Southern Oscillation, Pacific Decadal Oscillation, North Atlantic Oscillation, and Atlantic Multidecadal Oscillation) and monthly time series of electrical power production for over 1,500 hydropower reservoirs—obtained via simulation with a high-fidelity dam model forced with 20th century climate conditions. Notably significant relationships between electrical power productions and climate variability are found in many climate sensitive regions globally, including North and South America, East Asia, West Africa, and Europe. Coupled interactions from multiple, simultaneous climate drivers are also evaluated. Finally, we highlight the importance of using these climate drivers as an additional source of information within reservoir operating rules where the skillful predictability of inflow exists.

Global latitudinal species diversity gradient in deep-sea benthic foraminifera

NASA Astrophysics Data System (ADS)

Culver, Stephen J.; Buzas, Martin A.

2000-02-01

Global scale patterns of species diversity for modern deep-sea benthic foraminifera, an important component of the bathyal and abyssal meiofauna, are examined using comparable data from five studies in the Atlantic, ranging over 138° of latitude from the Norwegian Sea to the Weddell Sea. We show that a pattern of decreasing diversity with increasing latitude characterises both the North and South Atlantic. This pattern is confirmed for the northern hemisphere by independent data from the west-central North Atlantic and the Arctic basin. Species diversity in the North Atlantic northwards from the equator is variable until a sharp fall in the Norwegian Sea (ca. 65°N). In the South Atlantic species diversity drops from a maximum in latitudes less than 30°S and then decreases slightly from 40 to 70°S. For any given latitude, North Atlantic diversity is generally lower than in the South Atlantic. Both ecological and historical factors related to food supply are invoked to explain the formation and maintenance of the latitudinal gradient of deep-sea benthic foraminiferal species diversity. The gradient formed some 36 million years ago when global climatic cooling led to seasonally fluctuating food supply in higher latitudes.

Qualitative assessment of climate-driven ecological shifts in the Caspian Sea

PubMed Central

Beyraghdar Kashkooli, Omid; Gröger, Joachim; Núñez-Riboni, Ismael

2017-01-01

The worldwide occurrence of complex climate-induced ecological shifts in marine systems is one of the major challenges in sustainable bio-resources management. The occurrence of ecological environment-driven shifts was studied in the Southern Caspian Sea using the “shiftogram” method on available fisheries-related (i.e. commercially important bentho-pelagic fish stocks) ecological and climatic variables. As indicators of potential environmentally driven shift patterns we used indices for the North Atlantic Oscillation, the Southern Oscillation, the Siberian High, the East Atlantic-West Russia pattern, as well as Sea Surface Temperature and surface chlorophyll-a concentration. Given the explorative findings from the serial shift analyses, the cascading and serial order of multiple shift events in climatic-ecologic conditions of the southern Caspian Sea suggested a linkage between external forces and dynamics of ecosystem components and structures in the following order: global-scale climate forces lead to local environmental processes, which in turn lead to biological components dynamics. For the first time, this study indicates that ecological shifts are an integral component of bentho-pelagic subsystem regulatory processes and dynamics. Qualitative correspondence of biological responses of bentho-pelagic stocks to climatic events is one of the supporting evidences that overall Caspian ecosystem structures and functioning might have–at least partially–been impacted by global-scale climatic or local environmental shifts. These findings may help to foster a regional Ecosystem-based Approach to Management (EAM) as an integral part of bentho-pelagic fisheries management plans. PMID:28475609

33 CFR 167.155 - Off New York: Southern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.155 Off New York: Southern approach. (a) A...

33 CFR 167.153 - Off New York: Eastern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.153 Off New York: Eastern approach. (a) A...

33 CFR 167.153 - Off New York: Eastern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.153 Off New York: Eastern approach. (a) A...

33 CFR 167.155 - Off New York: Southern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.155 Off New York: Southern approach. (a) A...

33 CFR 167.153 - Off New York: Eastern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.153 Off New York: Eastern approach. (a) A...

33 CFR 167.155 - Off New York: Southern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.155 Off New York: Southern approach. (a) A...

33 CFR 167.155 - Off New York: Southern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.155 Off New York: Southern approach. (a) A...

33 CFR 167.155 - Off New York: Southern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.155 Off New York: Southern approach. (a) A...

33 CFR 167.153 - Off New York: Eastern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.153 Off New York: Eastern approach. (a) A...

33 CFR 167.153 - Off New York: Eastern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.153 Off New York: Eastern approach. (a) A...

Potential Impact of North Atlantic Climate Variability on Ocean Biogeochemical Processes

NASA Astrophysics Data System (ADS)

Liu, Y.; Muhling, B.; Lee, S. K.; Muller-Karger, F. E.; Enfield, D. B.; Lamkin, J. T.; Roffer, M. A.

2016-02-01

Previous studies have shown that upper ocean circulations largely determine primary production in the euphotic layers, here the global ocean model with biogeochemistry (GFDL's Modular Ocean Model with TOPAZ biogeochemistry) forced with the ERA-Interim is used to simulate the natural variability of biogeochemical processes in global ocean during 1979-present. Preliminary results show that the surface chlorophyll is overall underestimated in MOM-TOPAZ, but its spatial pattern is fairly realistic. Relatively high chlorophyll variability is shown in the subpolar North Atlantic, northeastern tropical Atlantic, and equatorial Atlantic. Further analysis suggests that the chlorophyll variability in the North Atlantic Ocean is affected by long-term climate variability. For the subpolar North Atlantic region, the chlorophyll variability is light-limited and is significantly correlated with North Atlantic Oscillation. A dipole pattern of chlorophyll variability is found between the northeastern tropical Atlantic and equatorial Atlantic. For the northeastern North Atlantic, the chlorophyll variability is significantly correlated with Atlantic Meridional Mode (AMM) and Atlantic Multidecadal Oscillation (AMO). During the negative phase of AMM and AMO, the increased trade wind in the northeast North Atlantic can lead to increased upwelling of nutrients. In the equatorial Atlantic region, the chlorophyll variability is largely link to Atlantic-Niño and associated equatorial upwelling of nutrients. The potential impact of climate variability on the distribution of pelagic fishes (i.e. yellowfin tuna) are discussed.

Holocene forest dynamics in central and western Mediterranean: periodicity, spatio-temporal patterns and climate influence.

PubMed

Di Rita, Federico; Fletcher, William J; Aranbarri, Josu; Margaritelli, Giulia; Lirer, Fabrizio; Magri, Donatella

2018-06-12

It is well-known that the Holocene exhibits a millennial-scale climate variability. However, its periodicity, spatio-temporal patterns and underlying processes are not fully deciphered yet. Here we focus on the central and western Mediterranean. We show that recurrent forest declines from the Gulf of Gaeta (central Tyrrhenian Sea) reveal a 1860-yr periodicity, consistent with a ca. 1800-yr climate fluctuation induced by large-scale changes in climate modes, linked to solar activity and/or AMOC intensity. We show that recurrent forest declines and dry events are also recorded in several pollen and palaeohydrological proxy-records in the south-central Mediterranean. We found coeval events also in several palaeohydrological records from the south-western Mediterranean, which however show generally wet climate conditions, indicating a spatio-temporal hydrological pattern opposite to the south-central Mediterranean and suggesting that different expressions of climate modes occurred in the two regions at the same time. We propose that these opposite hydroclimate regimes point to a complex interplay of the prevailing or predominant phases of NAO-like circulation, East Atlantic pattern, and extension and location of the North African anticyclone. At a larger geographical scale, displacements of the ITCZ, modulated by solar activity and/or AMOC intensity, may have also indirectly influenced the observed pattern.

Planktonic benthonic foraminiferal ratios: Modern patterns and Tertiary applicability

USGS Publications Warehouse

Gibson, T.G.

1989-01-01

The abundance of planktonic specimens in foraminiferal assemblages was determined in numerous bottom samples from inner neritic to deep oceanic depths along the Atlantic margin of the northeastern United States. The results augment previous studies in other areas that have shown a general increase in percentage of planktonic specimens in total foraminiferal bottom assemblages as water depth increases. The patterns found in this area of complex shelf bathymetry and hydrography illustrate the influence on the planktonic-benthonic percentages of water depth, distance from shore, different water mass properties and downslope movement of tests in high energy areas. The patterns found in the 661 samples from the Atlantic margin were compared with results from 795 stations in the Gulf of Mexico, Pacific Ocean and Red Sea. The relative abundance of planktonic specimens and water depth correlates positively in all open oceanic areas even though taxonomic composition and diversity of the faunas from different areas is variable. The variation of planktonic percentages in bottom samples within most depth intervals is large so that a precise depth determination cannot be made for any given value. However, an approximate upper depth limit for given percentages can be estimated for open ocean environments. A decrease in planktonic percentages is seen in the lower salinity and higher turbidity coastal waters of the Gulf of Maine. Planktonic percentages intermediate between the lower values in the less saline coastal waters and the higher values in the normal open oceanic conditions occur in the transitional area between the Gulf of Maine and the open marine Atlantic Ocean to the east. Similarly lowered values in another area of restricted oceanic circulation occur in the high salinity, clear, but nutrient-poor waters of the Gulf of Aqaba off the Red Sea. A comparison of the similarity of modern planktonic percentage values to those found in earlier Tertiary assemblages was made to confirm the usefulness of this measure in the fossil record. In some stratigraphic sections in upper Paleocene and lower Eocene strata of the eastern Gulf Coastal Plain, water depths inferred from trends and values of planktonic percentages consistently match paleobathymetry constructed from physical stratigraphic characteristics and paleogeographic relationships. ?? 1989.

Global meteorological influences on the record UK rainfall of winter 2013-14

NASA Astrophysics Data System (ADS)

Knight, Jeff R.; Maidens, Anna; Watson, Peter A. G.; Andrews, Martin; Belcher, Stephen; Brunet, Gilbert; Fereday, David; Folland, Chris K.; Scaife, Adam A.; Slingo, Julia

2017-07-01

The UK experienced record average rainfall in winter 2013-14, leading to widespread and prolonged flooding. The immediate cause of this exceptional rainfall was a very strong and persistent cyclonic atmospheric circulation over the North East Atlantic Ocean. This was related to a very strong North Atlantic jet stream which resulted in numerous damaging wind storms. These exceptional meteorological conditions have led to renewed questions about whether anthropogenic climate change is noticeably influencing extreme weather. The regional weather pattern responsible for the extreme UK winter coincided with highly anomalous conditions across the globe. We assess the contributions from various possible remote forcing regions using sets of ocean-atmosphere model relaxation experiments, where winds and temperatures are constrained to be similar to those observed in winter 2013-14 within specified atmospheric domains. We find that influences from the tropics were likely to have played a significant role in the development of the unusual extra-tropical circulation, including a role for the tropical Atlantic sector. Additionally, a stronger and more stable stratospheric polar vortex, likely associated with a strong westerly phase of the stratospheric Quasi-Biennial Oscillation (QBO), appears to have contributed to the extreme conditions. While intrinsic climatic variability clearly has the largest effect on the generation of extremes, results from an analysis which segregates circulation-related and residual rainfall variability suggest that emerging climate change signals made a secondary contribution to extreme rainfall in winter 2013-14.

Land - Ocean Climate Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian Ocean

NASA Astrophysics Data System (ADS)

Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp

2009-04-01

The past 5 Ma were marked by systematic shifts towards colder climates and concomitant reorganizations in ocean circulation and marine heat transports. Some of the changes involved plate-tectonic shifts such as the closure of the Panamanian Isthmus and restructuring of the Indonesian archipelago that affected inter-ocean communications and altered the world ocean circulation. These changes induced ocean-atmosphere feedbacks with consequences for climates globally and locally. Two new ICDP and IODP drilling initiatives target these developments from the perspectives of marine and terrestrial palaeoclimatology and the human evolution. The ICDP drilling initiative HSPDP ("Hominid Sites and Paleolakes Drilling Project"; ICDP ref. no. 10/07) targets lacustrine depocentres in Ethiopia (Hadar) and Kenya (West Turkana, Olorgesailie, Magadi) to retrieve sedimentary sequences close to the places and times where various species of hominins lived over currently available outcrop records. The records will provide a spatially resolved record of the East African environmental history in conjunction with climate variability at orbital (Milankovitch) and sub-orbital (ENSO decadal) time scales. HSPDP specifically aims at (1) compiling master chronologies for outcrops around each of the depocentres; (2) assessing which aspects of the paleoenvironmental records are a function of local origin (hydrology, hydrogeology) and which are linked with regional or larger-scale signals; (3) correlating broad-scale patterns of hominin phylogeny with the global beat of climate variability and (4) correlating regional shifts in the hominin fossil and archaeological record with more local patterns of paleoenvironmental change. Ultimately the aim is to test hypotheses that link physical and cultural adaptations in the course of the hominin evolution to local environmental change and variability. The IODP initiative SAFARI ("Southern African Climates, Agulhas Warm Water Transports and Retroflection, and Interocean Exchanges"; IODP ref. no. 702-full) aims at deciphering the late Neogene ocean history of the SW Indian Ocean. SAFARI specifically targets the Agulhas Current in the SW Indian Ocean that constitutes the strongest western boundary current in the southern hemisphere oceans. The Current transports warm and saline surface waters from the tropical Indian Ocean to the southern tip of Africa. Exchanges with the atmosphere influence eastern and southern African climates including individual weather systems such as extra-tropical cyclone formation in the region and rainfall patterns. Ocean models further suggest the "leakage" of Agulhas water around South Africa into the Atlantic potentially modulates the Atlantic meridional overturning circulation (MOC) with consequences for climate globally. The SAFARI drilling initiative aims to retrieve a suite of long drill cores along the southeast African margin and in the Indian-Atlantic ocean gateway. SAFARI will shed light on the history of Agulhas Current warm water transports along the southeast African margin during the late Neogene and its linking with ocean-climate developments. Specific objectives of SAFARI are to test (1) the sensitivity of the Agulhas Current to changing climates of the Plio/Pleistocene, including upstream forcing linked with equatorial Indian Ocean changes and Indonesian Throughflow; (2) the Current's influence on eastern and southern Africa climates, including rain fall patterns and vegetation changes; (3) buoyancy transfer to the Atlantic by Agulhas leakage around southern Africa, and (4) the contribution of variable Agulhas Leakage to shifts of the Atlantic MOC during episodes of major ocean and climate reorganizations of the past 5 Ma. These studies will provide insight into the Current's influence on eastern and southern African terrestrial climates, including its possible impact on the late Neogene evolution of large mammals including hominids. The ICDP and IODP drilling campaigns will enable us to establish the linkages between the ocean climatology of the SW Indian and terrestrial climates of Eastern Africa during key periods of global climate change. Combining the ICDP records of East African terrestrial climate at key hominin sites with IODP records of marine climate variability at the SE African continental margin will help to test if pulses of hominin evolutionary innovation were linked with periods of enhanced variability of local terrestrial environments and marine climatology of the Indian Ocean. * co-PIs of the ICDP initiative HSPDP are A.S. Cohen, R. Arrowsmith, A.K. Behrensmeyer, C. Feibel, R. Johnson, Z. Kubsa, D. Olago, R. Potts, R. Renaut * co-PIs of the IODP initiative SAFARI are R. Zahn, I. Hall, R. Schneider, M. Á. Bárcena, S. Barker, A. Biastoch, Chr. Charles, J. Compton, R. Cowling, P. Diz, L. Dupont, J.-A. Flores, S. Goldstein, S. Hemming, K. Holmgren, J. Lee-Thorp, G. Knorr, C. Lear, A. Mazaud, G. Mortyn, F. Peeters, B. Preu, R. Rickaby, J. Rogers, A. Rosell-Mele, Chr. Reason, V. Spiess, M. Trauth, G. Uenzelmann-Neben, S. Weldeab, P. Ziveri

Observations of Aerosol-Radiation-Cloud Interactions in the South-East Atlantic: First Results from the ORACLES Deployments in 2016 and 2017

NASA Technical Reports Server (NTRS)

Redemann, Jens; Wood, R.; Zuidema, P.; Diner, D.; Van Harten, G.; Xu, F.; Cairns, B.; Knobelspiesse, K.; Segal Rozenhaimer, M.

2017-01-01

Southern Africa produces almost a third of the Earths biomass burning (BB) aerosol particles. Particles lofted into the mid-troposphere are transported westward over the South-East (SE) Atlantic, home to one of the three permanent subtropical stratocumulus (Sc) cloud decks in the world. The SE Atlantic stratocumulus deck interacts with the dense layers of BB aerosols that initially overlay the cloud deck, but later subside and often mix into the clouds. These interactions include adjustments to aerosol-induced solar heating and microphysical effects, and their global representation in climate models remains one of the largest uncertainties in estimates of future climate. Hence, new observations over the SE Atlantic have significant implications for regional and global climate change predictions.The low-level clouds in the SE Atlantic have limited vertical extent and therefore present favorable conditions for their exploration with remote sensing. On the other hand, the normal coexistence of BB aerosols and Sc clouds in the same scene also presents significant challenges to conventional remote sensing techniques. We describe first results from NASAs airborne ORACLES (ObseRvations of Aerosols Above Clouds and Their IntEractionS) deployments in September 2016 and August 2017. We emphasize the unique role of polarimetric observations by two instruments, the Research Scanning Polarimeter (RSP) and the Airborne Multi-angle SpectroPolarimeter Imager (AirMSPI), and describe how these instruments help address specific ORACLES science objectives. Initial assessments of polarimetric observation accuracy for key cloud and aerosol properties will be presented, in as far as the preliminary nature of measurements permits.

Pb sbnd Sr sbnd Nd isotopic data of Indian Ocean ridges: new evidence of large-scale mapping of mantle heterogeneities

NASA Astrophysics Data System (ADS)

Hamelin, Bruno; Dupré, Bernard; Allègre, Claude J.

1986-01-01

A Pb sbnd Sr sbnd Nd isotope study of South West and East Indian Ridges confirms that the Indian Ocean belongs to a specific regional isotopic domain, as previously suggested by the results from islands of this ocean. The isotopic domain defined by the Indian MORB is indeed different from that of the North Atlantic and East Pacific Oceans. This demonstrates that the convective circulation of the upper mantle does not allow a rapid homogenization from one region to the other. The isotopic data of the Indian ridges can be interpreted by a contamination model, in which the depleted upper mantle (identical to that under the North Atlantic) is contaminated by two different types of contaminant, one corresponding to the source of the "central Indian Ocean" islands (Amsterdam, St. Paul, Marion, Prince Edward, Réunion, Rodriguez, Mauritius), and the other to a source similar to that of Walvis or Ninety East aseismic ridges. These two contaminants would have contributed to the ridge volcanism in different proportions over time.

Bird distributional patterns support biogeographical histories and are associated with bioclimatic units in the Atlantic Forest, Brazil.

PubMed

Carvalho, Cristiano DE Santana; Nascimento, Nayla Fábia Ferreira DO; Araujo, Helder F P DE

2017-10-17

Rivers as barriers to dispersal and past forest refugia are two of the hypotheses proposed to explain the patterns of biodiversity in the Atlantic Forest. It has recently been shown that possible past refugia correspond to bioclimatically different regions, so we tested whether patterns of shared distribution of bird taxa in the Atlantic Forest are 1) limited by the Doce and São Francisco rivers or 2) associated with the bioclimatically different southern and northeastern regions. We catalogued lists of forest birds from 45 locations, 36 in the Atlantic forest and nine in Amazon, and used parsimony analysis of endemicity to identify groups of shared taxa. We also compared differences between these groups by permutational multivariate analysis of variance and identified the species that best supported the resulting groups. The results showed that the distribution of forest birds is divided into two main regions in the Atlantic Forest, the first with more southern localities and the second with northeastern localities. This distributional pattern is not delimited by riverbanks, but it may be associated with bioclimatic units, surrogated by altitude, that maintain current environmental differences between two main regions on Atlantic Forest and may be related to phylogenetic histories of taxa supporting the two groups.

Tenarife Island, Canary Island Archipelago, Atlantic Ocean

NASA Technical Reports Server (NTRS)

1991-01-01

Tenarife Island is one of the most volcanically active of the Canary Island archipelago, Atlantic Ocean, just off the NW coast of Africa, (28.5N, 16.5W). The old central caldera, nearly filled in by successive volcanic activity culminating in two stratocones. From those two peaks, a line of smaller cinder cones extend to the point of the island. Extensive gullies dissect the west side of the island and some forests still remain on the east side.

Tenarife Island, Canary Island Archipelago, Atlantic Ocean

NASA Image and Video Library

1991-08-11

Tenarife Island is one of the most volcanically active of the Canary Island archipelago, Atlantic Ocean, just off the NW coast of Africa, (28.5N, 16.5W). The old central caldera, nearly filled in by successive volcanic activity culminating in two stratocones. From those two peaks, a line of smaller cinder cones extend to the point of the island. Extensive gullies dissect the west side of the island and some forests still remain on the east side.

China in the Middle East: The Wary Dragon

DTIC Science & Technology

2016-12-05

use. For information on reprint and linking permissions, please visit www.rand.org/pubs/permissions. The RAND Corporation is a research organization ...in Central Asia, the Middle East, and beyond. Further west, North Atlantic Treaty Organization (NATO) member countries, located some distance away...2011 and 2013, and Yemen in 2015, all organized by PRC civilian ministries, including the Ministry of Foreign Affairs, but none of these—except Yemen

View of debris assembled at the Kennedy Space Center from STS 51-L

NASA Technical Reports Server (NTRS)

1986-01-01

Large portion of the three main engines of the Space Shuttle Orbiter Challenger have been recovered from the floor of the Atlantic Ocean to the east of the Kennedy Space Center. They have been moved to a large storage building to the east of the Logistics Facility at Complex 39. Most of the pieces were recovered by the Coast Guard and Navy following the accident.

33 CFR 167.152 - Off New York: Eastern approach, off Nantucket.

Code of Federal Regulations, 2012 CFR

2012-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.152 Off New York: Eastern...

33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.203 In the...

33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.203 In the...

33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.203 In the...

33 CFR 167.152 - Off New York: Eastern approach, off Nantucket.

Code of Federal Regulations, 2013 CFR

2013-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.152 Off New York: Eastern...

33 CFR 167.154 - Off New York: South-eastern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.154 Off New York: South-eastern approach...

33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.203 In the...

33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.201 In the...

33 CFR 167.154 - Off New York: South-eastern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.154 Off New York: South-eastern approach...

33 CFR 167.154 - Off New York: South-eastern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.154 Off New York: South-eastern approach...

33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.203 In the...

33 CFR 167.173 - Off Delaware Bay: Two-Way Traffic Route.

Code of Federal Regulations, 2011 CFR

2011-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.173 Off Delaware Bay: Two-Way Traffic...

33 CFR 167.152 - Off New York: Eastern approach, off Nantucket.

Code of Federal Regulations, 2011 CFR

2011-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.152 Off New York: Eastern...

33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.201 In the...

33 CFR 167.173 - Off Delaware Bay: Two-Way Traffic Route.

Code of Federal Regulations, 2012 CFR

2012-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.173 Off Delaware Bay: Two-Way Traffic...

33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

Code of Federal Regulations, 2012 CFR

2012-07-01

... OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.202 In the...

33 CFR 167.173 - Off Delaware Bay: Two-Way Traffic Route.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.173 Off Delaware Bay: Two-Way Traffic...

33 CFR 167.154 - Off New York: South-eastern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.154 Off New York: South-eastern approach...

33 CFR 167.154 - Off New York: South-eastern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.154 Off New York: South-eastern approach...

33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.201 In the...

33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

Code of Federal Regulations, 2013 CFR

2013-07-01

... OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.202 In the...

33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.201 In the...

33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

Code of Federal Regulations, 2014 CFR

2014-07-01

... OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.202 In the...

33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

Code of Federal Regulations, 2011 CFR

2011-07-01

... OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.202 In the...

33 CFR 167.152 - Off New York: Eastern approach, off Nantucket.

Code of Federal Regulations, 2010 CFR

2010-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.152 Off New York: Eastern...

33 CFR 167.173 - Off Delaware Bay: Two-Way Traffic Route.

Code of Federal Regulations, 2013 CFR

2013-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.173 Off Delaware Bay: Two-Way Traffic...

33 CFR 167.152 - Off New York: Eastern approach, off Nantucket.

Code of Federal Regulations, 2014 CFR

2014-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.152 Off New York: Eastern...

33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

Code of Federal Regulations, 2010 CFR

2010-07-01

... OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.202 In the...

33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.201 In the...

33 CFR 167.173 - Off Delaware Bay: Two-Way Traffic Route.

Code of Federal Regulations, 2014 CFR

2014-07-01

... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.173 Off Delaware Bay: Two-Way Traffic...

Distribution, abundance and habitat use of deep diving cetaceans in the North-East Atlantic

NASA Astrophysics Data System (ADS)

Rogan, Emer; Cañadas, Ana; Macleod, Kelly; Santos, M. Begoña; Mikkelsen, Bjarni; Uriarte, Ainhize; Van Canneyt, Olivier; Vázquez, José Antonio; Hammond, Philip S.

2017-07-01

In spite of their oceanic habitat, deep diving cetacean species have been found to be affected by anthropogenic activities, with potential population impacts of high intensity sounds generated by naval research and oil prospecting receiving the most attention. Improving the knowledge of the distribution and abundance of this poorly known group is an essential prerequisite to inform mitigation strategies seeking to minimize their spatial and temporal overlap with human activities. We provide for the first time abundance estimates for five deep diving cetacean species (sperm whale, long-finned pilot whale, northern bottlenose whale, Cuvier's beaked whale and Sowerby's beaked whale) using data from three dedicated cetacean sighting surveys that covered the oceanic and shelf waters of the North-East Atlantic. Density surface modelling was used to obtain model-based estimates of abundance and to explore the physical and biological characteristics of the habitat used by these species. Distribution of all species was found to be significantly related to depth, distance from the 2000m depth contour, the contour index (a measure of variability in the seabed) and sea surface temperature. Predicted distribution maps also suggest that there is little spatial overlap between these species. Our results represent the best abundance estimates for deep-diving whales in the North-East Atlantic, predict areas of high density during summer and constitute important baseline information to guide future risk assessments of human activities on these species, evaluate potential spatial and temporal trends and inform EU Directives and future conservation efforts.

Habitat suitability of the Atlantic bluefin tuna by size class: An ecological niche approach

NASA Astrophysics Data System (ADS)

Druon, Jean-Noël; Fromentin, Jean-Marc; Hanke, Alex R.; Arrizabalaga, Haritz; Damalas, Dimitrios; Tičina, Vjekoslav; Quílez-Badia, Gemma; Ramirez, Karina; Arregui, Igor; Tserpes, George; Reglero, Patricia; Deflorio, Michele; Oray, Isik; Saadet Karakulak, F.; Megalofonou, Persefoni; Ceyhan, Tevfik; Grubišić, Leon; MacKenzie, Brian R.; Lamkin, John; Afonso, Pedro; Addis, Piero

2016-03-01

An ecological niche modelling (ENM) approach was used to predict the potential feeding and spawning habitats of small (5-25 kg, only feeding) and large (>25 kg) Atlantic bluefin tuna (ABFT), Thunnus thynnus, in the Mediterranean Sea, the North Atlantic and the Gulf of Mexico. The ENM was built bridging knowledge on ecological traits of ABFT (e.g. temperature tolerance, mobility, feeding and spawning strategy) with patterns of selected environmental variables (chlorophyll-a fronts and concentration, sea surface current and temperature, sea surface height anomaly) that were identified using an extensive set of precisely geo-located presence data. The results highlight a wider temperature tolerance for larger fish allowing them to feed in the northern - high chlorophyll levels - latitudes up to the Norwegian Sea in the eastern Atlantic and to the Gulf of Saint Lawrence in the western basin. Permanent suitable feeding habitat for small ABFT was predicted to be mostly located in temperate latitudes in the North Atlantic and in the Mediterranean Sea, as well as in subtropical waters off north-west Africa, while summer potential habitat in the Gulf of Mexico was found to be unsuitable for both small and large ABFTs. Potential spawning grounds were found to occur in the Gulf of Mexico from March-April in the south-east to April-May in the north, while favourable conditions evolve in the Mediterranean Sea from mid-May in the eastern to mid-July in the western basin. Other secondary potential spawning grounds not supported by observations were predicted in the Azores area and off Morocco to Senegal during July and August when extrapolating the model settings from the Gulf of Mexico into the North Atlantic. The presence of large ABFT off Florida and the Bahamas in spring was not explained by the model as is, however the environmental variables other than the sea surface height anomaly appeared to be favourable for spawning in part of this area. Defining key spatial and temporal habitats should further help in building spatially-explicit stock assessment models, thus improving the spatial management of bluefin tuna fisheries.

The crust and upper mantle of central East Greenland - implications for continental accretion and rift evolution

NASA Astrophysics Data System (ADS)

Schiffer, Christian; Balling, Niels; Ebbing, Jörg; Holm Jacobsen, Bo; Bom Nielsen, Søren

2016-04-01

The geological evolution of the North Atlantic Realm during the past 450 Myr, which has shaped the present-day topographic, crustal and upper mantle features, was dominated by the Caledonian orogeny and the formation of the North Atlantic and associated igneous activity. The distinct high altitude-low relief landscapes that accompany the North Atlantic rifted passive margins are the focus of a discussion of whether they are remnant and modified Caledonian features or, alternatively, recently uplifted peneplains. Teleseismic receiver function analysis of 11 broadband seismometers in the Central Fjord Region in East Greenland indicates the presence of a fossil subduction complex, including a slab of eclogitised mafic crust and an overlying wedge of hydrated mantle peridotite. This model is generally consistent with gravity and topography. It is shown that the entire structure including crustal thickness variations and sub-Moho heterogeneity gives a superior gravity and isostatic topographic fit compared to a model with a homogeneous lithospheric layer (1). The high topography of >1000 m in the western part of the area is supported by the c. 40 km thick crust. The eastern part requires buoyancy from the low velocity/low density mantle wedge. The geometry, velocities and densities are consistent with structures associated with a fossil subduction zone. The spatial relations with Caledonian structures suggest a Caledonian origin. The results indicate that topography is isostatically compensated by density variations within the lithosphere and that significant present-day dynamic topography seems not to be required. Further, this structure is suggested to be geophysically very similar to the Flannan reflector imaged north of Scotland, and that these are the remnants of the same fossil subduction zone, broken apart and separated during the formation of the North Atlantic in the early Cenozoic (2). 1) Schiffer, C., Jacobsen, B.H., Balling, N., Ebbing, J. and Nielsen, S.B., 2015. The East Greenland Caledonides - teleseismic signature, gravity and isostasy. Geophysical Journal International, 203, 1400-1418. 2) Schiffer, C., Stephenson, R.A., Petersen, K.D., Nielsen, S.B., Jacobsen, B.H., Balling, N. and Macdonald, D.I.M., 2015. A sub-crustal piercing point for North Atlantic reconstructions and tectonic implications. Geology, 43, 1087-1090.

Observations of Aerosol-Cloud Interactions with Varying Vertical Separation between Biomass-Burning Aerosols and Stratocumulus Clouds over the South East Atlantic

NASA Astrophysics Data System (ADS)

Gupta, S.; McFarquhar, G. M.; Poellot, M.; O'Brien, J.; Delene, D. J.; Thornhill, K. L., II

2017-12-01

The ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES) 2016 project provided in-situ measurements and remotely sensed retrievals of aerosol and cloud properties over the South East Atlantic during September, 2016 with a second deployment scheduled for August, 2017. Biomass burning aerosol from Southern Africa is advected toward the South East Atlantic at elevated altitudes and overlies the ubiquitous stratocumulus cloud deck over the ocean. The aerosols subside farther from the coast so that the vertical displacement between the clouds and aerosols varies, and whose effect on aerosol-cloud interaction is poorly known. A NASA P-3 aircraft was equipped with a Cloud Droplet Probe CDP sizing particles between 2 and 50μm, a Cloud and Aerosol Spectrometer CAS sizing between 0.51 and 50 μm and a 2D-stereo probe 2DS, nominally sizing between 10 and 1280 μm a Cloud Imaging Probe CIP, from 25 to 1600μm, and a High Volume Precipitation Sampler HVPS-3, from 150μm to 1.92cm for measuring number distribution functions (n(D)) along with a King probe for measuring liquid water content, LWC. A Passive Cavity Aerosol Spectrometer Probe PCASP measured aerosol particles between 0.1 to 3μm. Cloud legs from three research flights are classified into different regimes based on the aerosol concentration measured in the accumulation mode by the PCASP (Na) and its location above clouds. These legs include vertical transects through clouds and sawtooths (ramped legs starting above or below the cloud layer, completing a vertical transect through the cloud and repeating this pattern for several legs). The regimes; clean, mixing and separated, correspond to conditions with Na less than 100 cm-3 above cloud top, Na greater than 100 cm-3 within 100 m above cloud top and Na greater than 100 cm-3 separated from the cloud top by more than 100 m. During the mixing regime, measurements from CAS and 2DS show that droplet concentrations and cloud optical depths increased and effective radii decreased, relative to other regimes. Drizzle suppression with lower probability of occurrence of drizzle drops (diameter greater than 50 um) and entrainment of dry air with decreased droplet concentrations near cloud tops was also observed. Similar LWC was observed across regimes with similar vertical velocities during the cloud legs.

Seasonal detours by soaring migrants shaped by wind regimes along the East Atlantic Flyway.

PubMed

Vansteelant, Wouter M G; Shamoun-Baranes, Judy; van Manen, Willem; van Diermen, Jan; Bouten, Willem

2017-03-01

Avian migrants often make substantial detours between their seasonal destinations. It is likely some species do this to make the most of predictable wind regimes along their respective flyways. We test this hypothesis by studying orientation behaviour of a long-distance soaring migrant in relation to prevailing winds along the East Atlantic Flyway. We tracked 62 migratory journeys of 12 adult European Honey Buzzards Pernis apivorus with GPS loggers. Hourly fixes were annotated with local wind vectors from a global atmospheric model to determine orientation behaviours with respect to the buzzards' seasonal goal destinations. This enabled us to determine hot spots where buzzards overdrifted and overcompensated for side winds. We then determined whether winds along the buzzards' detours differed from winds prevailing elsewhere in the flyway. Honey Buzzards cross western Africa using different routes in autumn and spring. In autumn, they overcompensated for westward winds to circumvent the Atlas Mountains on the eastern side and then overdrifted with south-westward winds while crossing the Sahara. In spring, however, they frequently overcompensated for eastward winds to initiate a westward detour at the start of their journey. They later overdrifted with side winds north-westward over the Sahel and north-eastward over the Sahara, avoiding adverse winds over the central Sahara. We conclude that Honey Buzzards make seasonal detours to utilize more supportive winds further en route and thereby expend less energy while crossing the desert. Lifelong tracking studies will be helpful to elucidate how honey buzzards and other migrants learn complex routes to exploit atmospheric circulation patterns from local to synoptic scales. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

11. DETAIL OF TERRACOTTA DECORATION, SHOWING SCROLL CONSOLE, WAVE ORNAMENT, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. DETAIL OF TERRACOTTA DECORATION, SHOWING SCROLL CONSOLE, WAVE ORNAMENT, EGG-AND-DART, NYMPH HEADS AND FOLIATE PATTERN AROUND WINDOWS - City Hall, Atlantic & Tennessee Avenues, Atlantic City, Atlantic County, NJ

Effects of smallmouth bass (Micropterus dolomeiu) on Atlantic salmon (Salmo salar) habitat use and diel movements in an artificial stream.

USGS Publications Warehouse

Zydlewski, Joseph D.; Coghlan, Stephen M.; Trial, Joan G.; Wathen, Gus

2012-01-01

Invasive smallmouth bass Micropterus dolomieu have been introduced to some of the last remaining watersheds that contain wild anadromous Atlantic salmon Salmo salar, yet little is known about the interactions between these species. We used an artificial stream equipped with passive integrated transponder tag antenna arrays to monitor habitat use and movements of age-0 Atlantic salmon and age-0 smallmouth bass in sympatry and allopatry. We used additive and substitutive designs to test for changes in habitat use, diel movements, and diel activity patterns of prior-resident Atlantic salmon or smallmouth bass resulting from the addition of conspecifics or heterospecifics. Atlantic salmon prior residents did not change their habitat use in the presence of conspecific or heterospecific invaders. However, Atlantic salmon invaders did lessen riffle habitat use by smallmouth bass prior residents during daytime. Atlantic salmon and smallmouth bass displayed different diel activity patterns of movement (Atlantic salmon were more nocturnal; smallmouth bass were more diurnal), which were affected by heterospecific introductions. Because the two species tended to favor different habitat types and displayed different diel activity patterns, we suggest that under the conditions tested, the level of interspecific competition for habitat was low. Age-0 Atlantic salmon and smallmouth bass may be able to avoid intense interspecific competition through spatial and temporal habitat partitioning. These data do not, however, predict the potential for competition under different seasonal or ontogenetic circumstances.

Walker Circulation, El Niño and La Niña

NASA Astrophysics Data System (ADS)

Halpern, D.

2014-12-01

Ocean surface wind vector is likely the critical variable to predict onset, maintenance and dissipation of El Niño and La Niña. Analyses of SeaWinds and ASCAT 10-m height (called "surface") vector winds in the Atlantic, Indian and Pacific Oceans from 1°S-1°N during March 2000 - June 2011 revealed the longitudinal distribution of the surface zonal wind component associated with the Walker Circulation. In the Pacific Ocean east of 140°E and west of 85°W, the mean wind direction was westward towards the maritime continent with maximum mean zonal wind speed (- 6.5 m s-1) at 150°W; east of 85°W the mean direction was toward the convection zone over South America. Four El Niños and five La Niñas occurred from March 2000 - June 2011. In the Pacific from 150°E to 160°W, the average El Niño (La Niña) westward wind speed was 2 m s-1 (1 m s-1) smaller (larger) than normal. In the west Pacific, the variation in westward wind speeds in El Niño and La Niña conditions relative to normal conditions would be expected to substantially uplift the thermocline during El Niño compared to La Niña, which is consistent with conventional wisdom. In the east Pacific from 130°W - 100°W, average El Niño westward wind speeds were less than normal and La Niña conditions by 0.5 m s-1 and 1 m s-1, respectively. The "central" Pacific nature of the El Niños may have influenced the smaller difference between El Niño and La Niña westward wind speeds in the east Pacific compared to the west Pacific. Analyses of longitudinal distributions of thermocline depths will be discussed. Surface zonal wind speeds in the Atlantic and Indian Oceans showed no evidence of El Niño and La Niña; surface meridional winds showed an apparent response in the Indian and Pacific Oceans but not in the Atlantic Ocean. At 700-m height, the MISR zonal wind component in the Atlantic, Indian and Pacific Oceans had similar features as those at the surface, except in the east Pacific where the westward wind speeds were identical during El Niño, La Niña and normal conditions. In the east Pacific, the shear between 10- and 700-m heights increased (decreased) during La Niña (El Niño).

North Atlantic SST Patterns and NAO Flavors

NASA Astrophysics Data System (ADS)

Rousi, E.; Rahmstorf, S.; Coumou, D.

2017-12-01

North Atlantic SST variability results from the interaction of atmospheric and oceanic processes. The North Atlantic Oscillation (NAO) drives changes in SST patterns but is also driven by them on certain time-scales. These interactions are not very well understood and might be affected by anthropogenic climate change. Paleo reconstructions indicate a slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in recent decades leading to a pronounced cold anomaly ("cold blob") in the North Atlantic (Rahmstorf et al., 2015). The latter may favor NAO to be in its negative mode. In this work, sea surface temperature (SST) patterns are studied in relation to NAO variations, with the aim of discovering preferred states and understanding their interactions. SST patterns are analyzed with Self-Organizing Maps (SOM), a clustering technique that helps identify different spatial patterns and their temporal evolution. NAO flavors refer to different longitudinal positions and tilts of the NAO action centers, also defined with SOMs. This way the limitations of the basic, index-based, NAO-definition are overcome, and the method handles different spatially shapes associated with NAO. Preliminary results show the existence of preferred combinations of SSTs and NAO flavors, which in turn affect weather and climate of Europe and North America. The possible influence of the cold blob on European weather is discussed.

Synchronicity of the East Asian Summer Monsoon variability and Northern Hemisphere climate change since the last deglaciation

NASA Astrophysics Data System (ADS)

Shinozaki, T.; Uchida, M.; Minoura, K.; Kondo, M.; Rella, S. F.; Shibata, Y.

2011-06-01

Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8 m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based on 42 14C measurements, the core bottom reaches ~15.5 ka. δ13C, accumulation rate and accumulation flux time-series correlate well to Greenland ice core δ18O variability, suggesting that the climate record in Northeast Japan is linked to global climate changes. The δ13C record at Tashiro Bog and other paleo-EASM records at Northeast and Southern China consistently demonstrate that hydrological environments were spatially different in mid-high and mid-low latitude regions over the last 15.5 kyr. During global cooling (warming) periods, mid-high and mid-low latitude regions were characterized by wet (dry) and dry (wet) environments, respectively. We suggest that these climatic patterns are related to the migration of the EASM-related rain belt during global climate changes, as a consequence of variations in intensity and location of both the Intertropical Convergence Zone (ITCZ) and the Western Pacific Subtropical High (STH). The location of the rain belt largely influences the East Asian hydrological environment. Our δ13C time-series are characterized by a 1230 yr throughout the Holocene and a 680 yr periodicity during the early Holocene. The 1230 yr periodicity is in agreement with North Atlantic ice-rafted debris (IRD) events, suggesting a teleconnection between the Northeast Japan and the North Atlantic during the Holocene. In addition, it is the first evidence that the Bond events were recorded in terrestrial sediment in Japan. On the other hand, the 680 yr periodicity between 10.0 and 8.0 kyr is consistent with a prominent 649 yr solar activity cycle, suggesting that solar activity affected EASM precipitation during the Hypsithermal, when orbital-scale solar insolation was at a maximum in the Northern Hemisphere.

2. Historic American Buildings Survey, Copied by Survey Photographer (e) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Historic American Buildings Survey, Copied by Survey Photographer (e) Ext-Old Photograph- Gen View North and East Elevations, (before 1868) - India Wharf Stores, 306-308 Atlantic Avenue, Boston, Suffolk County, MA

47 CFR 73.205 - Zones.

Code of Federal Regulations, 2012 CFR

2012-10-01

... consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located...; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a...

47 CFR 73.205 - Zones.

Code of Federal Regulations, 2011 CFR

2011-10-01

... consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located...; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a...

47 CFR 73.205 - Zones.

Code of Federal Regulations, 2013 CFR

2013-10-01

... consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located...; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a...

47 CFR 73.205 - Zones.

Code of Federal Regulations, 2014 CFR

2014-10-01

... consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located...; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a...

47 CFR 73.205 - Zones.

Code of Federal Regulations, 2010 CFR

2010-10-01

...; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a... consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located...

33 CFR 167.251 - In the approaches to the Cape Fear River: Precautionary area.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.251 In the...

33 CFR 167.251 - In the approaches to the Cape Fear River: Precautionary area.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.251 In the...

33 CFR 167.251 - In the approaches to the Cape Fear River: Precautionary area.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.251 In the...

33 CFR 167.251 - In the approaches to the Cape Fear River: Precautionary area.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.251 In the...

12. October 1972. INTERIOR VIEW OF ROOF TRUSS SYSTEM. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. October 1972. INTERIOR VIEW OF ROOF TRUSS SYSTEM. - Atlantic & Great Western Railroad, Meadville Repair Shops, Blacksmith Shop, East bank of French Creek, 800 feet South of Spring Street, Meadville, Crawford County, PA

Influence of Western Tibetan Plateau Summer Snow Cover on East Asian Summer Rainfall

NASA Astrophysics Data System (ADS)

Wang, Zhibiao; Wu, Renguang; Chen, Shangfeng; Huang, Gang; Liu, Ge; Zhu, Lihua

2018-03-01

The influence of boreal winter-spring eastern Tibetan Plateau snow anomalies on the East Asian summer rainfall variability has been the focus of previous studies. The present study documents the impacts of boreal summer western and southern Tibetan Plateau snow cover anomalies on summer rainfall over East Asia. Analysis shows that more snow cover in the western and southern Tibetan Plateau induces anomalous cooling in the overlying atmospheric column. The induced atmospheric circulation changes are different corresponding to more snow cover in the western and southern Tibetan Plateau. The atmospheric circulation changes accompanying the western Plateau snow cover anomalies are more obvious over the midlatitude Asia, whereas those corresponding to the southern Plateau snow cover anomalies are more prominent over the tropics. As such, the western and southern Tibetan Plateau snow cover anomalies influence the East Asian summer circulation and precipitation through different pathways. Nevertheless, the East Asian summer circulation and precipitation anomalies induced by the western and southern Plateau snow cover anomalies tend to display similar distribution so that they are more pronounced when the western and southern Plateau snow cover anomalies work in coherence. Analysis indicates that the summer snow cover anomalies over the Tibetan Plateau may be related to late spring snow anomalies due to the persistence. The late spring snow anomalies are related to an obvious wave train originating from the western North Atlantic that may be partly associated with sea surface temperature anomalies in the North Atlantic Ocean.

Large Tabular Iceberg, South Atlantic Ocean

NASA Image and Video Library

1991-09-18

This large tabular iceberg, broken off from the Antarctic Ice Sheet, was spotted in the South Atlantic Ocean (57.0S, 57.0W) southeast of the tip of South America as it was slowly being moved north and east by wind, current and tidal influences. This type of iceberg, never to be seen in the northern hemisphere, is typical for Antarctica. Although some such icebergs are as large as 100 km in length, this one measures about 35 by 69 km.

Large Tabular Iceberg, South Atlantic Ocean

NASA Technical Reports Server (NTRS)

1991-01-01

This large tabular iceberg, broken off from the Antarctic Ice Sheet, was spotted in the South Atlantic Ocean (57.0S, 57.0W) southeast of the tip of South America as it was slowly being moved north and east by wind, current and tidal influences. This type of iceberg, never to be seen in the northern hemisphere, is typical for Antarctica. Although some such icebergs are as large as 100 km in length, this one measures about 35 by 69 km.

Potential links between the North Atlantic Oscillation and decreasing precipitation and runoff on Sardinia

NASA Astrophysics Data System (ADS)

Montaldo, Nicola; Sarigu, Alessio

2017-04-01

Recently, climate change and human activities increased the desertification process in the Mediterranean regions, with dramatic consequences for agriculture and water resources. On the Sardinia island (Italy), runoff decreased significantly in the 1975-2010 period with a mean yearly runoff reduction of more than 50% compared to the previous 1922-1974 period. The decrease in runoff severely impacts the management of water resources on the Sardinia island, resulting in water supply restrictions even for domestic consumption. In the 10 Sardinian basins, with a longer database (at least 40 complete years of data, including data from the past 10 years), the trend of yearly runoff computed with the Mann-Kendall test is negative, with the Mann-Kendall τ values ranging from -0.39 to -0.2. The reason for the decrease in runoff is mainly the alarming decrease in the winter precipitation over the past few decades everywhere on the Sardinia island. Indeed, most of the yearly runoff of the Sardinian basins (on average, 70%) is produced by the winter precipitation due to the typical seasonality of the Mediterranean rainfall regime. Surprisingly, the winter precipitation trend is not homogenous; the negative trend is higher on the Sardinian west coast and becomes lower as one crosses the island toward the east coast. At the rain stations on the east coast, the τ Mann-Kendall values of the winter precipitation become almost half of the τ Mann-Kendall values on the west coast, which is exposed to the western European climate dynamics. In this sense, winter precipitation is highly correlated with the North Atlantic Oscillation (NAO), which is a weather phenomenon in the North Atlantic Ocean that controls the direction and strength of westerly winds and storm tracks into Europe. High negative correlations (up to -0.45) between winter NAO and winter precipitation are estimated along the west coast. Meanwhile, the correlations decrease as one crosses the island toward the east, encounters the high mountain in the center of Sardinia, and reaches the lowest values on the east coast (about -0.25). Hence, the general decreasing trend in the correlation between winter NAO and precipitation along the longitudinal direction (from the North Atlantic dipole to the east) is accelerating here due to local-scale topographic effects that overlap the large-scale NAO impact and affect the winter precipitation regime, thus softening the NAO impact on precipitation reduction.

Secular spring rainfall variability at local scale over Ethiopia: trend and associated dynamics

NASA Astrophysics Data System (ADS)

Tsidu, Gizaw Mengistu

2017-10-01

Spring rainfall secular variability is studied using observations, reanalysis, and model simulations. The joint coherent spatio-temporal secular variability of gridded monthly gauge rainfall over Ethiopia, ERA-Interim atmospheric variables and sea surface temperature (SST) from Hadley Centre Sea Ice and SST (HadISST) data set is extracted using multi-taper method singular value decomposition (MTM-SVD). The contemporaneous associations are further examined using partial Granger causality to determine presence of causal linkage between any of the climate variables. This analysis reveals that only the northwestern Indian Ocean secular SST anomaly has direct causal links with spring rainfall over Ethiopia and mean sea level pressure (MSLP) over Africa inspite of the strong secular covariance of spring rainfall, SST in parts of subtropical Pacific, Atlantic, Indian Ocean and MSLP. High secular rainfall variance and statistically significant linear trend show consistently that there is a massive decline in spring rain over southern Ethiopia. This happened concurrently with significant buildup of MSLP over East Africa, northeastern Africa including parts of the Arabian Peninsula, some parts of central Africa and SST warming over all ocean basins with the exception of the ENSO regions. The east-west pressure gradient in response to the Indian Ocean warming led to secular southeasterly winds over the Arabian Sea, easterly over central Africa and equatorial Atlantic. These flows weakened climatological northeasterly flow over the Arabian Sea and southwesterly flow over equatorial Atlantic and Congo basins which supply moisture into the eastern Africa regions in spring. The secular divergent flow at low level is concurrent with upper level convergence due to the easterly secular anomalous flow. The mechanisms through which the northwestern Indian Ocean secular SST anomaly modulates rainfall are further explored in the context of East Africa using a simplified atmospheric general circulation model (AGCM) coupled to mixed-layer oceanic model. The rainfall anomaly (with respect to control simulation), forced by the northwestern Indian Ocean secular SST anomaly and averaged over the 30-year period, exhibits prevalence of dry conditions over East and equatorial Africa in agreement with observation. The atmospheric response to secular SST warming anomaly led to divergent flow at low levels and subsidence at the upper troposphere over regions north of 5° S on the continent and vice versa over the Indian Ocean. This surface difluence over East Africa, in addition to its role in suppressing convective activity, deprives the region of moisture supply from the Indian Ocean as well as the Atlantic and Congo basins.

Offshore Observations of Eastern Red Bats (Lasiurus borealis) in the Mid-Atlantic United States Using Multiple Survey Methods

PubMed Central

Hatch, Shaylyn K.; Connelly, Emily E.; Divoll, Timothy J.; Stenhouse, Iain J.; Williams, Kathryn A.

2013-01-01

Little is known about the migration and movements of migratory tree-roosting bat species in North America, though anecdotal observations of migrating bats over the Atlantic Ocean have been reported since at least the 1890s. Aerial surveys and boat-based surveys of wildlife off the Atlantic Seaboard detected a possible diurnal migration event of eastern red bats (Lasiurus borealis) in September 2012. One bat was sighted approximately 44 km east of Rehoboth Beach, Delaware during a boat-based survey. Eleven additional bats were observed between 16.9 and 41.8 km east of New Jersey, Delaware, and Virginia in high definition video footage collected during digital aerial surveys. Observations were collected incidentally as part of a large baseline study of seabird, marine mammal, and sea turtle distributions and movements in the offshore environment. Digital survey methods also allowed for altitude estimation for several of these bats at >100 m above sea level. These observations provide new evidence of bat movements offshore, and offer insight into their flight heights above sea level and the times of day at which such migrations may occur. PMID:24367614

The Relationships between Tropical Pacific and Atlantic SST and Northeast Brazil Monthly Precipitation.

NASA Astrophysics Data System (ADS)

Bertacchi Uvo, Cintia; Repelli, Carlos A.; Zebiak, Stephen E.; Kushnir, Yochanan

1998-04-01

The monthly patterns of northeast Brazil (NEB) precipitation are analyzed in relation to sea surface temperature (SST) in the tropical Pacific and Atlantic Oceans, using singular value decomposition. It is found that the relationships between precipitation and SST in both basins vary considerably throughout the rainy season (February-May). In January, equatorial Pacific SST is weakly correlated with precipitation in small areas of southern NEB, but Atlantic SST shows no significant correlation with regional precipitation. In February, Pacific SST is not well related to precipitation, but south equatorial Atlantic SST is positively correlated with precipitation over the northern Nordeste, the latter most likely reflecting an anomalously early (or late) southward migration of the ITCZ precipitation zone. During March, equatorial Pacific SST is negatively correlated with Nordeste precipitation, but no consistent relationship between precipitation and Atlantic SST is found. Atlantic SST-precipitation correlations for April and May are the strongest found among all months or either ocean. Precipitation in the Nordeste is positively correlated with SST in the south tropical Atlantic and negatively correlated with SST in the north tropical Atlantic. These relationships are strong enough to determine the structure of the seasonal mean SST-precipitation correlations, even though the corresponding patterns for the earlier months of the season are quite different. Pacific SST-precipitation correlations for April and May are similar to those for March. Extreme wet (dry) years for the Nordeste occur when both Pacific and Atlantic SST patterns for April and May occur simultaneously. A separate analysis reinforces previous findings in showing that SST in the tropical Pacific and the northern tropical Atlantic are positively correlated and that tropical Pacific-south Atlantic correlations are negligible.Time-lagged analyses show the potential for forecasting either seasonal mean or monthly precipitation patterns with some degree of skill. In some instances, individual monthly mean SST versus seasonal mean (February-May) precipitation relationships differ considerably from the corresponding monthly SST versus monthly precipitation relationships. It is argued that the seasonal mean relationships result from the relatively strong monthly relationships toward the end of the season, combined with the considerable persistence of SST in both oceans.

A synoptic and dynamical characterization of wave-train and blocking cold surge over East Asia

NASA Astrophysics Data System (ADS)

Park, Tae-Won; Ho, Chang-Hoi; Deng, Yi

2014-08-01

Through an agglomerative hierarchical clustering method, cold surges over East Asia are classified into two distinct types based on the spatial pattern of the geopotential height anomalies at 300 hPa. One is the wave-train type that is associated with developing large-scale waves across the Eurasian continent. The other is the blocking type whose occurrence accompanies subarctic blocking. During the wave-train cold surge, growing baroclinic waves induce a southeastward expansion of the Siberian High and strong northerly winds over East Asia. Blocking cold surge, on the other hand, is associated with a southward expansion of the Siberian High and northeasterly winds inherent to a height dipole consisting of the subarctic blocking and the East Asian coastal trough. The blocking cold surge tends to be more intense and last longer compared to the wave-train type. The wave-train cold surge is associated with the formation of a negative upper tropospheric height anomaly southeast of Greenland approximately 12 days before the surge occurrence. Further analysis of isentropic potential vorticity reveals that this height anomaly could originate from the lower stratosphere over the North Atlantic. Cold surge of the blocking type occurs with an amplifying positive geopotential and a negative potential vorticity anomaly over the Arctic and the northern Eurasia in stratosphere. These anomalies resemble the stratospheric signature of a negative phase of the Arctic Oscillation. This stratospheric feature is further demonstrated by the observation that the blocking type cold surge occurs more often when the Arctic Oscillation is in its negative phase.

Human Activities on the Deep Seafloor in the North East Atlantic: An Assessment of Spatial Extent

PubMed Central

Benn, Angela R.; Weaver, Philip P.; Billet, David S. M.; van den Hove, Sybille; Murdock, Andrew P.; Doneghan, Gemma B.; Le Bas, Tim

2010-01-01

Background Environmental impacts of human activities on the deep seafloor are of increasing concern. While activities within waters shallower than 200 m have been the focus of previous assessments of anthropogenic impacts, no study has quantified the extent of individual activities or determined the relative severity of each type of impact in the deep sea. Methodology The OSPAR maritime area of the North East Atlantic was chosen for the study because it is considered to be one of the most heavily impacted by human activities. In addition, it was assumed data would be accessible and comprehensive. Using the available data we map and estimate the spatial extent of five major human activities in the North East Atlantic that impact the deep seafloor: submarine communication cables, marine scientific research, oil and gas industry, bottom trawling and the historical dumping of radioactive waste, munitions and chemical weapons. It was not possible to map military activities. The extent of each activity has been quantified for a single year, 2005. Principal Findings Human activities on the deep seafloor of the OSPAR area of the North Atlantic are significant but their footprints vary. Some activities have an immediate impact after which seafloor communities could re-establish, while others can continue to make an impact for many years and the impact could extend far beyond the physical disturbance. The spatial extent of waste disposal, telecommunication cables, the hydrocarbon industry and marine research activities is relatively small. The extent of bottom trawling is very significant and, even on the lowest possible estimates, is an order of magnitude greater than the total extent of all the other activities. Conclusions/Significance To meet future ecosystem-based management and governance objectives for the deep sea significant improvements are required in data collection and availability as well as a greater awareness of the relative impact of each human activity. PMID:20856885

Human activities on the deep seafloor in the North East Atlantic: an assessment of spatial extent.

PubMed

Benn, Angela R; Weaver, Philip P; Billet, David S M; van den Hove, Sybille; Murdock, Andrew P; Doneghan, Gemma B; Le Bas, Tim

2010-09-13

Environmental impacts of human activities on the deep seafloor are of increasing concern. While activities within waters shallower than 200 m have been the focus of previous assessments of anthropogenic impacts, no study has quantified the extent of individual activities or determined the relative severity of each type of impact in the deep sea. The OSPAR maritime area of the North East Atlantic was chosen for the study because it is considered to be one of the most heavily impacted by human activities. In addition, it was assumed data would be accessible and comprehensive. Using the available data we map and estimate the spatial extent of five major human activities in the North East Atlantic that impact the deep seafloor: submarine communication cables, marine scientific research, oil and gas industry, bottom trawling and the historical dumping of radioactive waste, munitions and chemical weapons. It was not possible to map military activities. The extent of each activity has been quantified for a single year, 2005. Human activities on the deep seafloor of the OSPAR area of the North Atlantic are significant but their footprints vary. Some activities have an immediate impact after which seafloor communities could re-establish, while others can continue to make an impact for many years and the impact could extend far beyond the physical disturbance. The spatial extent of waste disposal, telecommunication cables, the hydrocarbon industry and marine research activities is relatively small. The extent of bottom trawling is very significant and, even on the lowest possible estimates, is an order of magnitude greater than the total extent of all the other activities. To meet future ecosystem-based management and governance objectives for the deep sea significant improvements are required in data collection and availability as well as a greater awareness of the relative impact of each human activity.

SPATIAL PATTERNS AND ECOLOGICAL DETERMINANTS OF BENTHIC ALGAL ASSEMBLAGES IN MID-ATLANTIC STREAMS, USA

EPA Science Inventory

We attempted to identify spatial patterns and determinants for benthic algal assemblages in Mid-Atlantic streams. Periphyton, water chemistry, stream physical habitat, riparian conditions, and land cover/use in watersheds were characterized at 89 randomly selected stream sites i...

7. October 1972. INTERIOR VIEW, SHOWING THE ROOF TRUSS SYSTEM. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. October 1972. INTERIOR VIEW, SHOWING THE ROOF TRUSS SYSTEM. - Atlantic & Great Western Railroad, Meadville Repair Shops, Blacksmith Shop, East bank of French Creek, 800 feet South of Spring Street, Meadville, Crawford County, PA

Observations of aerosol-induced convective invigoration in the tropical east Atlantic

NASA Astrophysics Data System (ADS)

Storer, R. L.; van den Heever, S. C.; L'Ecuyer, T. S.

2014-04-01

Four years of CloudSat data have been analyzed over a region of the east Atlantic Ocean in order to examine the influence of aerosols on deep convection. The satellite data were combined with information about aerosols taken from the Global and Regional Earth-System Monitoring Using Satellite and In Situ Data model. Only those profiles fitting the definition of deep convective clouds were analyzed. Overall, the cloud center of gravity, cloud top, and rain top were all found to increase with increased aerosol loading. These effects were largely independent of the environment, and the differences between the cleanest and most polluted clouds sampled were found to be statistically significant. When examining an even smaller subset of deep convective clouds likely to be part of the convective core, similar trends were seen. These observations suggest that convective invigoration occurs with increased aerosol loading, leading to deeper, stronger storms in polluted environments.

Suspended particulate loads and transports in the nepheloid layer of the abyssal Atlantic Ocean

USGS Publications Warehouse

Biscaye, P.E.; Eittreim, S.L.

1977-01-01

Vertical profiles of light scattering from over 1000 L-DGO nephelometer stations in the Atlantic Ocean have been used to calculate mass concentrations of suspended particles based on a calibration from the western North American Basin. From these data are plotted the distributions of particulate concentrations at clear water and in the more turbid near-bottom water. Clear water is the broad minimum in concentration and light scattering that occurs at varying mid-depths in the water column. Concentrations at clear water are as much as one-to-two orders of magnitude lower than those in surface water but still reflect a similar geographic distribution: relatively higher concentrations at ocean margins, especially underneath upwelling areas, and the lowest concentrations underneath central gyre areas. These distributions within the clear water reflect surface-water biogenic productivity, lateral injection of particles from shelf areas and surface circulation patterns and require that the combination of downward vertical and horizontal transport processes of particles retain this pattern throughout the upper water column. Below clear water, the distribution of standing crops of suspended particulate concentrations in the lower water column are presented. The integration of mass of all particles per unit area (gross particulate standing crop) reflects a relative distribution similar to that at the surface and at clear water levels, superimposed on which is the strong imprint of boundary currents along the western margins of the Atlantic. Reducing the gross particulate standing crop by the integral of the concentration of clear water yields a net particulate standing crop. The distribution of this reflects primarily the interaction of circulating abyssal waters with the ocean bottom, i.e. a strong nepheloid layer which is coincident with western boundary currents and which diminishes in intensity equatorward. The resuspended particulate loads in the nepheloid layer of the basins west of the Mid-Atlantic Ridge, resulting from interaction of abyssal currents with the bottom, range from ??? 2 ?? 106 tons in the equatorial Guyana Basin to ??? 50 ?? 106 tons in the North American Basin. The total resuspended particulate load in the western basins (111 ?? 106 tons) is almost an order of magnitude greater than that in the basins east of the Mid-Atlantic Ridge (13 ?? 106 tons). The net northward flux of resuspended particles carried in the AABW drops from ??? 8 ?? 106 tons/year between the southern and northern ends of the Brazil Basin and remains ??? 1 ?? 106 tons/year across the Guyana Basin. ?? 1977.

Patagonian and southern South Atlantic view of Holocene climate

NASA Astrophysics Data System (ADS)

Kaplan, M. R.; Schaefer, J. M.; Strelin, J. A.; Denton, G. H.; Anderson, R. F.; Vandergoes, M. J.; Finkel, R. C.; Schwartz, R.; Travis, S. G.; Garcia, J. L.; Martini, M. A.; Nielsen, S. H. H.

2016-06-01

We present a comprehensive 10Be chronology for Holocene moraines in the Lago Argentino basin, on the east side of the South Patagonian Icefield. We focus on three different areas, where prior studies show ample glacier moraine records exist because they were formed by outlet glaciers sensitive to climate change. The 10Be dated records are from the Lago Pearson, Herminita Península-Brazo Upsala, and Lago Frías areas, which span a distance of almost 100 km adjacent to the modern Icefield. New 10Be ages show that expanded glaciers and moraine building events occurred at least at 6120 ± 390 (n = 13), 4450 ± 220 (n = 7), 1450 or 1410 ± 110 (n = 18), 360 ± 30 (n = 5), and 240 ± 20 (n = 8) years ago. Furthermore, other less well-dated glacier expansions of the Upsala Glacier occurred between 1400 and ∼1000 and ∼2300 and ∼2000 years ago. The most extensive glaciers occurred over the interval from ∼6100 to ∼4500 years ago, and their margins over the last ∼600 years were well within and lower than those in the middle Holocene. The 10Be ages agree with 14C-limiting data for the glacier histories in this area. We then link southern South American, adjacent South Atlantic, and other Southern Hemisphere records to elucidate broader regional patterns of climate and their possible causes. In the early Holocene, a far southward position of the westerly winds fostered warmth, small Patagonian glaciers, and reduced sea ice coverage over the South Atlantic. Although we infer a pronounced southward displacement of the westerlies during the early Holocene, these conditions did not occur throughout the southern mid-high latitudes, an important exception being over the southwest Pacific sector. Subsequently, a northward locus and/or expansion of the winds over the Patagonia-South Atlantic sector promoted the largest glaciers between ∼6100 and ∼4500 years ago and greatest sea ice coverage. Over the last few millennia, the South Patagonian Icefield has experienced successive century-scale advances superimposed on a long-term net decrease in size. Our findings indicate that glaciers and sea ice in the Patagonian-South Atlantic sector of the Southern Hemisphere did not achieve their largest Holocene extents over the last millennium. We conclude that a pattern of more extensive Holocene ice prior to the last millennium is characteristic of the Southern Hemisphere middle latitudes, which differs from the glacier history traditionally thought for the Northern Hemisphere.

Aerosol-Radiation-Cloud Interactions in the South-East Atlantic: Future Suborbital Activities to Address Knowledge Gaps in Satellite and Model Assessments

NASA Technical Reports Server (NTRS)

Redemann, Jens; Wood, R.; Zuidema, P.; Haywood, J.; Piketh, S.; Formenti, P.; L'Ecuyer, T.; Kacenelenbogen, M.; Segal-Rosenheimer, M.; Shinozuka, Y.;

Aerosol-Radiation-Cloud Interactions in the South-East Atlantic: Future Suborbital Activities to Address Knowledge Gaps in Satellite and Model Assessments

NASA Astrophysics Data System (ADS)

Redemann, J.; Wood, R.; Zuidema, P.; Haywood, J. M.; Piketh, S.; Formenti, P.; L'Ecuyer, T. S.; Kacenelenbogen, M. S.; Segal-Rosenhaimer, M.; Shinozuka, Y.; LeBlanc, S. E.; Vaughan, M. A.; Schmidt, S.; Flynn, C. J.; Song, S.; Schmid, B.; Luna, B.; Abel, S.

2015-12-01

Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles. Particles lofted into the mid-troposphere are transported westward over the South-East (SE) Atlantic, home to one of the three permanent subtropical stratocumulus (Sc) cloud decks in the world. The SE Atlantic stratocumulus deck interacts with the dense layers of BB aerosols that initially overlay the cloud deck, but later subside and may mix into the clouds. These interactions include adjustments to aerosol-induced solar heating and microphysical effects, and their global representation in climate models remains one of the largest uncertainties in estimates of future climate. Hence, new observations over the SE Atlantic have significant implications for global climate change scenarios. Our understanding of aerosol-cloud interactions in the SE Atlantic is hindered both by the lack of knowledge on aerosol and cloud properties, as well as the lack of knowledge about detailed physical processes involved. Most notably, we are missing knowledge on the absorptive and cloud nucleating properties of aerosols, including their vertical distribution relative to clouds, on the locations and degree of aerosol mixing into clouds, on the processes that govern cloud property adjustments, and on the importance of aerosol effects on clouds relative to co-varying synoptic scale meteorology. We discuss the current knowledge of aerosol and cloud property distributions based on satellite observations and sparse suborbital sampling. Recent efforts to make full use of A-Train aerosol sensor synergies will be highlighted. We describe planned field campaigns in the region to address the existing knowledge gaps. Specifically, we describe the scientific objectives and implementation of the five synergistic, international research activities aimed at providing some of the key aerosol and cloud properties and a process-level understanding of aerosol-cloud interactions over the SE Atlantic: NASA's ORACLES, the UK Met Office's CLARIFY-2016, the DoE's LASIC, NSF's ONFIRE, and CNRS' AEROCLO-SA.

Reconstructed streamflow in the eastern United States: validity, drivers, and challenges

NASA Astrophysics Data System (ADS)

Maxwell, S.; Harley, G. L.; Maxwell, J. T.; Rayback, S. A.; Pederson, N.; Cook, E. R.; Barclay, D. J.; Li, W.; Rayburn, J. A.

2015-12-01

Tree-ring reconstructions of streamflow are uncommon in the eastern US compared to the western US. While the eastern US does not experience severe drought on the scale of the west, multi-year droughts have stressed the water management systems throughout the east. Here, we reconstruct three rivers serving population centers in the northeast (Beaver Kill River serving New York City, NY), mid-Atlantic (Potomac River serving Washington, D.C.), and southeast (Flint River serving Atlanta, GA) to demonstrate the ability to reconstruct in the eastern US. Then, we conducted an interbasin comparison to identify periods of common variability and examined synoptic scale drivers of drought and pluvial events. Finally, we discuss the utility of multi-species reconstructions in the moist, biodiverse eastern US. Our calibration models explained 66 - 68% of the variance in the instrumental record and passed verification tests in all basins to 1675 CE. Drought and pluvial events showed some synchrony across all basins but the mid-Atlantic acted as a hinge, sometimes behaving more like the northeast, and other times like the southeast. Weak correlations with oceanic-atmospheric oscillations made identification of synoptic scale drivers difficult. However, there appears to be a relationship between the position of the western ridge of the North Atlantic Subtropical High and streamflow across the basins of the east. Given the many factors influencing tree growth in closed canopy systems, we have shown that careful standardization of individual tree-ring series, nested regression models, and the use of multiple species can produce robust proxies in the east.

Electrically-Active Convection in Tropical Easterly Waves and Implications for Tropical Cyclogenesis in the Atlantic and East Pacific

NASA Technical Reports Server (NTRS)

Leppert, Kenneth D., II; Petersen, Walter A.; Cecil, Daniel J.

2012-01-01

In this study, we investigate the characteristics of tropical easterly wave convection and the possible implications of convective structure on tropical cyclogenesis and intensification over the Atlantic Ocean and East Pacific using data from the Tropical Rainfall Measurement Mission Microwave Imager, Precipitation Radar (PR), and Lightning Imaging Sensor as well as infrared (IR) brightness temperature data from the NASA global-merged IR brightness temperature dataset. Easterly waves were partitioned into northerly, southerly, trough, and ridge phases based on the 700-hPa meridional wind from the NCEP-NCAR reanalysis dataset. Waves were subsequently divided according to whether they did or did not develop tropical cyclones (i.e., developing and nondeveloping, respectively), and developing waves were further subdivided according to development location. Finally, composites as a function of wave phase and category were created using the various datasets. Results suggest that the convective characteristics that best distinguish developing from nondeveloping waves vary according to where developing waves spawn tropical cyclones. For waves that developed a cyclone in the Atlantic basin, coverage by IR brightness temperatures .240 K and .210 K provide the best distinction between developing and nondeveloping waves. In contrast, several variables provide a significant distinction between nondeveloping waves and waves that develop cyclones over the East Pacific as these waves near their genesis location including IR threshold coverage, lightning flash rates, and low-level (<4.5 km) PR reflectivity. Results of this study may be used to help develop thresholds to better distinguish developing from nondeveloping waves and serve as another aid for tropical cyclogenesis forecasting.

76 FR 5340 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-31

... inclement weather, NMFS cancelled the Protected Species Safe Handling, Release, and Identification workshop..., 2011, due to inclement weather along the east coast of the United States on the date of the originally...

76 FR 7155 - Atlantic Highly Migratory Species; Announcement of Billfish and Swordfish Catch Card Pilot...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-09

... Office of Science and Technology, 1315 East West Highway, Silver Spring, MD 20910. FOR FURTHER... landings information. Marinas, tackle shops and other private businesses will be asked to serve as catch...

Potential links between the North Atlantic Oscillation and decreasing precipitation and runoff on a Mediterranean area

NASA Astrophysics Data System (ADS)

Montaldo, Nicola; Sarigu, Alessio

2017-10-01

In the Mediterranean region, the reduction in precipitation and warmer temperatures is generating a desertification process, with dramatic consequences for both agriculture and the sustainability of water resources. On the island of Sardinia (Italy), the decrease in runoff impacts the management of water resources, resulting in water supply restrictions even for domestic consumption. In the 10 Sardinian basins with a longer database (at least 40 complete years of data, including data from the past 10 years), runoff decreased drastically over the 1975-2010 period, with mean yearly runoff reduced by more than 40% compared to the previous 1922-1974 period. Trends in yearly runoff are negative, with Mann-Kendall τ values ranging from -0.39 to -0.2. Decreasing winter precipitation over the 1975-2010 period everywhere on Sardinia island has led to these decreases in runoff, as most yearly runoff in the Sardinian basins (70% on average) is produced by winter precipitation due to the seasonality typical of the Mediterranean climate regime. The trend in winter precipitation is not homogenous; the negative trend is higher (around -0.25) on the west Sardinian coast, becoming lower across the island toward the east coast (around -0.14). Winter precipitation is highly correlated with the North Atlantic Oscillation (NAO), a weather phenomenon in the North Atlantic Ocean that controls the direction and strength of westerly winds and storm tracks into Europe. High negative correlations (up to -0.45) between winter NAO index and winter precipitation are estimated along the west coast. Meanwhile, these correlations decrease east across the island toward the high mountain in the center of Sardinia, reaching the lowest values along the east coast (about -0.25). The generally decreasing correlation between winter NAO index and winter precipitation in the longitudinal direction (from the North Atlantic dipole to the east) here accelerates due to local-scale orographic effects that overlap the large-scale NAO impact on the winter precipitation regime, thus softening the precipitation reduction due to the NAO. Such local topographic effects that may attenuate large-scale climate change effects must be considered in water resource planning and management alongside such climate change effects related to large-scale circulations, such as NAO.

Potential links between the North Atlantic Oscillation and decreasing precipitation and runoff on Sardinia

NASA Astrophysics Data System (ADS)

Sarigu, A.; Montaldo, N.

2017-12-01

In the Mediterranean region, the reduction in precipitation and warmer temperatures is generating a desertification process, with dramatic consequences for both agriculture and the sustainability of water resources. On the island of Sardinia (Italy), the decrease in runoff impacts the management of water resources, resulting in water supply restrictions even for domestic consumption. In the 10 Sardinian basins with a longer database (at least 40 complete years of data, including data from the past 10 years), runoff decreased drastically over the 1975-2010 period, with mean yearly runoff reduced by more than 40% compared to the previous 1922-1974 period. Trends in yearly runoff are negative, with Mann-Kendall τ values ranging from -0.39 to -0.2. Decreasing winter precipitation over the 1975-2010 period everywhere on Sardinia island has led to these decreases in runoff, as most yearly runoff in the Sardinian basins (70% on average) is produced by winter precipitation due to the seasonality typical of the Mediterranean climate regime. The trend in winter precipitation is not homogenous; the negative trend is higher (around -0.25) on the west Sardinian coast, becoming lower across the island toward the east coast (around -0.14). Winter precipitation is highly correlated with the North Atlantic Oscillation (NAO), a weather phenomenon in the North Atlantic Ocean that controls the direction and strength of westerly winds and storm tracks into Europe. High negative correlations (up to -0.45) between winter NAO index and winter precipitation are estimated along the west coast. Meanwhile, these correlations decrease east across the island toward the high mountain in the center of Sardinia, reaching the lowest values along the east coast (about -0.25). The decreasing correlation between winter NAO index and winter precipitation in the longitudinal direction (from the North Atlantic dipole to the east) here accelerates due to local-scale orographic effects that overlap the large-scale NAO impact on the winter precipitation regime, thus softening the precipitation reduction due to the NAO. Such local topographic effects that may attenuate large-scale climate change effects must be considered in water resource planning and management alongside such climate change effects related to large-scale circulations, such as NAO.

Atlantic reef fish biogeography and evolution

USGS Publications Warehouse

Floeter, S.R.; Rocha, L.A.; Robertson, D.R.; Joyeux, J.C.; Smith-Vaniz, W.F.; Wirtz, P.; Edwards, A.J.; Barreiros, J.P.; Ferreira, C.E.L.; Gasparini, J.L.; Brito, A.; Falcon, J.M.; Bowen, B.W.; Bernardi, G.

2008-01-01

Aim: To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment. Location: Atlantic Ocean. Methods: The distributions of 2605 species of reef fishes were compiled for 25 areas of the Atlantic and southern Africa. Maximum-parsimony and distance analyses were employed to investigate biogeographical relationships among those areas. A collection of 26 phylogenies of various Atlantic reef fish taxa was used to assess patterns of origin and diversification relative to evolutionary scenarios based on spatio-temporal sequences of species splitting produced by geological and palaeoceanographic events. We present data on faunal (species and genera) richness, endemism patterns, diversity buildup (i.e. speciation processes), and evaluate the operation of the main biogeographical barriers and/or filters. Results: Phylogenetic (proportion of sister species) and distributional (number of shared species) patterns are generally concordant with recognized biogeographical provinces in the Atlantic. The highly uneven distribution of species in certain genera appears to be related to their origin, with highest species richness in areas with the greatest phylogenetic depth. Diversity buildup in Atlantic reef fishes involved (1) diversification within each province, (2) isolation as a result of biogeographical barriers, and (3) stochastic accretion by means of dispersal between provinces. The timing of divergence events is not concordant among taxonomic groups. The three soft (non-terrestrial) inter-regional barriers (mid-Atlantic, Amazon, and Benguela) clearly act as 'filters' by restricting dispersal but at the same time allowing occasional crossings that apparently lead to the establishment of new populations and species. Fluctuations in the effectiveness of the filters, combined with ecological differences among provinces, apparently provide a mechanism for much of the recent diversification of reef fishes in the Atlantic. Main conclusions: Our data set indicates that both historical events (e.g. Tethys closure) and relatively recent dispersal (with or without further speciation) have had a strong influence on Atlantic tropical marine biodiversity and have contributed to the biogeographical patterns we observe today; however, examples of the latter process outnumber those of the former. ?? 2007 The Authors.

Evolutionary diversity among Atlantic coast mangroves

NASA Astrophysics Data System (ADS)

Dodd, Richard S.; Rafii, Zara A.; Fromard, François; Blasco, François

1998-06-01

Current knowledge of intraspecific variation of mangrove species is limited in terms of rangewide distributions and is mostly restricted to morphological analyses, which have indicated a high degree of homogeneity. However, our analyses of the aliphatic hydrocarbon and triterpenoid fraction of foliar waxes (by gas chromatography and mass spectroscopy) of mangrove species ( Rhizophora mangle, Avicennia germinans and Laguncularia racemosa) from Gabon in West Africa and French Guiana in South America show significant genetic differentiation between eastern and western Atlantic provenances. The greater diversity in lipid composition, and the tendency for longer carbon chain lengths in all taxa from Africa, may suggest that American mangroves exhibit derived characteristics. A consequence of this hypothesis would be that Atlantic mangroves are unlikely to have dispersed from the Tethys via the Pacific, as has been proposed by some authors. More widespread sampling within the Atlantic and east Pacific region is needed to support and confirm these results.

On the occurrence of egg masses of the diamond-shaped squid Thysanoteuthis rhombus Troschel, 1857 in the subtropical eastern Atlantic (Canary Islands). A potential commercial species?

PubMed Central

Pérez, Alejandro Escánez; Elena, Rodrigo Riera; González, Ángel Francisco González; Sierra, Ángel Guerra

2012-01-01

Abstract Data on opportunistic sightings of diamond-shaped squid Thysanoteuthis rhombus egg masses in the Canary Islands (Atlantic Ocean) are presented. A total of 16 egg masses of this species were recorded and photographed from 2000 to 2010 around the western islands of the archipelago (El Hierro, Tenerife and La Gomera). These data reveal the existence of an important spawning area for diamond-shaped squid around the Canary Islands, in subtropical east Atlantic waters. We provide preliminary data for the potential development of an artisanal fishery focused on this species, and a discussion on its potential impacts on the marine ecosystem. PMID:23129987

Dispersal Routes and Habitat Utilization of Juvenile Atlantic Bluefin Tuna, Thunnus thynnus, Tracked with Mini PSAT and Archival Tags

PubMed Central

Galuardi, Benjamin; Lutcavage, Molly

2012-01-01

Between 2005 and 2009, we deployed 58 miniature pop-up satellite archival tags (PSAT) and 132 implanted archival tags on juvenile Atlantic bluefin tuna (age 2–5) in the northwest Atlantic Ocean. Data returned from these efforts (n = 26 PSATs, 1 archival tag) revealed their dispersal routes, horizontal and vertical movements and habitat utilization. All of the tagged bluefin tuna remained in the northwest Atlantic for the duration observed, and in summer months exhibited core-use of coastal seas extending from Maryland to Cape Cod, MA, (USA) out to the shelf break. Their winter distributions were more spatially disaggregated, ranging south to the South Atlantic Bight, northern Bahamas and Gulf Stream. Vertical habitat patterns showed that juvenile bluefin tuna mainly occupied shallow depths (mean  = 5–12 m, sd  = 15–23.7 m) and relatively warm water masses in summer (mean  = 17.9–20.9°C, sd  = 4.2–2.6°C) and had deeper and more variable depth patterns in winter (mean  = 41–58 m, sd  = 48.9–62.2 m). Our tagging results reveal annual dispersal patterns, behavior and oceanographic associations of juvenile Atlantic bluefin tuna that were only surmised in earlier studies. Fishery independent profiling from electronic tagging also provide spatially and temporally explicit information for evaluating dispersals rates, population structure and fisheries catch patterns. PMID:22629461

Decadal predictability of winter windstorm frequency in Eastern Europe

NASA Astrophysics Data System (ADS)

Höschel, Ines; Grieger, Jens; Ulbrich, Uwe

2017-04-01

Winter windstorms are one of the most impact relevant extreme-weather events in Europe. This study is focussed on windstorm frequency in Eastern Europe at multi-year time scale. Individual storms are identified by using 6-hourly 10m-wind-fields. The impact-oriented tracking algorithm is based on the exceedance of the local 98 percentile of wind speed and a minimum duration of 18 hours. Here, storm frequency is the number of 1000km-footprints of identified windstorms touching the location during extended boreal winter from October to March. The temporal development of annual storm frequencies in Eastern Europe shows variations on a six to fifteen years period. Higher than normal windstorm frequency occurred end of the 1950s and in beginning of the seventies, while lower than normal frequency were around 1960 and in the forties, for example. The correlation between bandpass filtered storm frequency and North Atlantic sea surface temperature shows a significant pattern with a positive correlation in the subtropical East Atlantic and significant negative correlations in the Gulfstream region. The relationship between these multi-year variations and predictability on decadal time scales is discussed. The resulting skill of winter wind storms in the German decadal prediction system MiKlip, based on the numerical earth system model MPI-ESM, will be presented.

Loire and Gironde turbid plumes: Characterization and influence on thermohaline properties

NASA Astrophysics Data System (ADS)

Costoya, X.; Fernández-Nóvoa, D.; deCastro, M.; Gómez-Gesteira, M.

2017-12-01

Knowledge and predictability of turbid river plumes is of great importance because they modulate the properties of the seawater adjacent to river mouths. The Loire and Gironde Rivers form the most important plumes in the Bay of Biscay, as they provide > 75% of total runoff. The development of the turbid plume under the influence of its main drivers was analyzed using Moderate Resolution Imaging Spectroradiometer satellite data from the period 2003-2015. River discharge was found to be the main driver, followed by wind, which also had an important effect in modulating the turbid plume during periods of high river discharge. Seaward and upwelling favorable winds enhanced the dispersion of plumes on seawater, whereas landward and downwelling favorable winds limited mixing with the adjacent ocean water. The maximum extension of the turbid plume was reached under landward winds. In addition, the spatio-temporal evolution of the East Atlantic pattern and the North Atlantic Oscillation was observed to affect the dynamics of plumes: positive values of both indices favored a greater extension of the plume. Thermohaline properties differed inside and outside the area affected by both rivers. In particular, these rivers maintain winter stratification inside the turbid plume, which results in a different warming ratio when compared with the adjacent ocean.

Immediate replacement of fishing with dairying by the earliest farmers of the northeast Atlantic archipelagos

PubMed Central

Cramp, Lucy J. E.; Jones, Jennifer; Sheridan, Alison; Smyth, Jessica; Whelton, Helen; Mulville, Jacqui; Sharples, Niall; Evershed, Richard P.

2014-01-01

The appearance of farming, from its inception in the Near East around 12 000 years ago, finally reached the northwestern extremes of Europe by the fourth millennium BC or shortly thereafter. Various models have been invoked to explain the Neolithization of northern Europe; however, resolving these different scenarios has proved problematic due to poor faunal preservation and the lack of specificity achievable for commonly applied proxies. Here, we present new multi-proxy evidence, which qualitatively and quantitatively maps subsistence change in the northeast Atlantic archipelagos from the Late Mesolithic into the Neolithic and beyond. A model involving significant retention of hunter–gatherer–fisher influences was tested against one of the dominant adoptions of farming using a novel suite of lipid biomarkers, including dihydroxy fatty acids, ω-(o-alkylphenyl)alkanoic acids and stable carbon isotope signatures of individual fatty acids preserved in cooking vessels. These new findings, together with archaeozoological and human skeletal collagen bulk stable carbon isotope proxies, unequivocally confirm rejection of marine resources by early farmers coinciding with the adoption of intensive dairy farming. This pattern of Neolithization contrasts markedly to that occurring contemporaneously in the Baltic, suggesting that geographically distinct ecological and cultural influences dictated the evolution of subsistence practices at this critical phase of European prehistory. PMID:24523264

Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters

PubMed Central

Gonçalves-Araujo, Rafael; Granskog, Mats A.; Bracher, Astrid; Azetsu-Scott, Kumiko; Dodd, Paul A.; Stedmon, Colin A.

2016-01-01

Climate change affects the Arctic with regards to permafrost thaw, sea-ice melt, alterations to the freshwater budget and increased export of terrestrial material to the Arctic Ocean. The Fram and Davis Straits represent the major gateways connecting the Arctic and Atlantic. Oceanographic surveys were performed in the Fram and Davis Straits, and on the east Greenland Shelf (EGS), in late summer 2012/2013. Meteoric (fmw), sea-ice melt, Atlantic and Pacific water fractions were determined and the fluorescence properties of dissolved organic matter (FDOM) were characterized. In Fram Strait and EGS, a robust correlation between visible wavelength fluorescence and fmw was apparent, suggesting it as a reliable tracer of polar waters. However, a pattern was observed which linked the organic matter characteristics to the origin of polar waters. At depth in Davis Strait, visible wavelength FDOM was correlated to apparent oxygen utilization (AOU) and traced deep-water DOM turnover. In surface waters FDOM characteristics could distinguish between surface waters from eastern (Atlantic + modified polar waters) and western (Canada-basin polar waters) Arctic sectors. The findings highlight the potential of designing in situ multi-channel DOM fluorometers to trace the freshwater origins and decipher water mass mixing dynamics in the region without laborious samples analyses. PMID:27667721

50 CFR 622.182 - Gear-restricted areas.

Code of Federal Regulations, 2014 CFR

2014-10-01

... scale NOAA chart of the location. A person aboard a vessel with a longline on board that fishes on a... the South Atlantic EEZ south of 28°35.1′ N. lat. (due east of the NASA Vehicle Assembly Building, Cape...

50 CFR 622.182 - Gear-restricted areas.

Code of Federal Regulations, 2013 CFR

2013-10-01

... scale NOAA chart of the location. A person aboard a vessel with a longline on board that fishes on a... the South Atlantic EEZ south of 28°35.1′ N. lat. (due east of the NASA Vehicle Assembly Building, Cape...

United States Air Force Statistical Digest, Fiscal Year 1992/1993 Estimate

DTIC Science & Technology

1993-01-01

UNCLASSIFIED am INo tATLANTIC ATLANTIC AZORES LAJES F1E1I(~_:’ -, PACIFIC EAST CHINA SEA o’,.-., ,D. r) OUDENA AB i »r MISAWA AB o o II ,. BONIN ISlSo c... Dave (OK) Foglietta, T.M. (PA) Hertel, Dennis M. (MI) Lloyd, Marilyn B. (TN) Sisisky, Norman (VA) Ray, Richard (GA) Spratt, John M., Jr. (SC...RI) Saxton, Jam" H. (NJ) Cunningham, Randy (Duke) (CA) Franke, Gary (CT) DEMOCRATS Dellums, ROO;lld (CA) Chmn. McCurdy, Dave (OK) Foglietta, Thomas

Environmental Assessment for the Beddown and Flight Operations of Unmanned Aircraft Systems at Cape Canaveral Air Force Station, Florida

DTIC Science & Technology

2011-07-01

Banana River to the west. PURPOSE AND NEED: The purpose of this action is to . establish a U.S. CBP A&M Southeastern Region Operations Center that...barrier island bordered by the Atlantic Ocean to the east and the Banana River to the west. CCAFS is home to the 45th Space Wing (45 SW) Mission...Hangar C Cape Canaveral AFS Skid Strip Figure 3-2. Cape Canaveral AFS Land Use July 20113-5Final EA Atlantic Ocean Banana River Legend CCAFS

ISS Pass Over Hurricane Jose and Hurricane Irma 9/8/17

NASA Image and Video Library

2017-09-08

The International Space Station passed over two major Atlantic hurricanes on Friday, Sept. 8. First, the station flew approximately 250 miles over Hurricane Jose at approximately 10:10 a.m. EDT while the Category 3 storm was in the Atlantic just east of the Caribbean. One orbit of the Earth later, the station flew over Hurricane Irma at approximately 11:40 a.m. EDT. The powerful Category 4 storm had already brought destructive wind and rain to islands across the Caribbean and is forecast to impact the Florida peninsula.

Novel biodiversity baselines outpace models of fish distribution in Arctic waters

NASA Astrophysics Data System (ADS)

Christiansen, Jørgen S.; Bonsdorff, Erik; Byrkjedal, Ingvar; Fevolden, Svein-Erik; Karamushko, Oleg V.; Lynghammar, Arve; Mecklenburg, Catherine W.; Møller, Peter D. R.; Nielsen, Julius; Nordström, Marie C.; Præbel, Kim; Wienerroither, Rupert M.

2016-02-01

During a recent marine biological expedition to the Northeast Greenland shelf break (latitudes 74-77 °N), we made the first discovery of Atlantic cod ( Gadus morhua), beaked redfish ( Sebastes mentella) and capelin ( Mallotus villosus). Our novel observations shift the distribution range of Atlantic cod >1000 km further north in East Greenland waters. In light of climate change, we discuss physical forcing and putative connections between the faunas of the Northeast Greenland shelf and the Barents Sea. We emphasise the importance of using real data in spread scenarios for understudied Arctic seas.

Novel biodiversity baselines outpace models of fish distribution in Arctic waters.

PubMed

Christiansen, Jørgen S; Bonsdorff, Erik; Byrkjedal, Ingvar; Fevolden, Svein-Erik; Karamushko, Oleg V; Lynghammar, Arve; Mecklenburg, Catherine W; Møller, Peter D R; Nielsen, Julius; Nordström, Marie C; Præbel, Kim; Wienerroither, Rupert M

2016-02-01

During a recent marine biological expedition to the Northeast Greenland shelf break (latitudes 74-77 °N), we made the first discovery of Atlantic cod (Gadus morhua), beaked redfish (Sebastes mentella) and capelin (Mallotus villosus). Our novel observations shift the distribution range of Atlantic cod >1000 km further north in East Greenland waters. In light of climate change, we discuss physical forcing and putative connections between the faunas of the Northeast Greenland shelf and the Barents Sea. We emphasise the importance of using real data in spread scenarios for understudied Arctic seas.

ASSOCIATIONS BETWEEN NAO VARIBILITY AND U.S. MID-ATLANTIC REGION HYDROCLIMATOLOGY

EPA Science Inventory

Variability in the climate of the US Mid-Atlantic Region is associated with larger scale variability in the El Nino-Southern Oscillation (ENSO), the Pacific North American (PNA) teleconnection pattern, and the North Atlantic Oscillation (NAO). Collectively, these three large-scal...

The North Atlantic Ocean Is in a State of Reduced Overturning

NASA Astrophysics Data System (ADS)

Smeed, D. A.; Josey, S. A.; Beaulieu, C.; Johns, W. E.; Moat, B. I.; Frajka-Williams, E.; Rayner, D.; Meinen, C. S.; Baringer, M. O.; Bryden, H. L.; McCarthy, G. D.

2018-02-01

The Atlantic Meridional Overturning Circulation (AMOC) is responsible for a variable and climatically important northward transport of heat. Using data from an array of instruments that span the Atlantic at 26°N, we show that the AMOC has been in a state of reduced overturning since 2008 as compared to 2004-2008. This change of AMOC state is concurrent with other changes in the North Atlantic such as a northward shift and broadening of the Gulf Stream and altered patterns of heat content and sea surface temperature. These changes resemble the response to a declining AMOC predicted by coupled climate models. Concurrent changes in air-sea fluxes close to the western boundary reveal that the changes in ocean heat transport and sea surface temperature have altered the pattern of ocean-atmosphere heat exchange over the North Atlantic. These results provide strong observational evidence that the AMOC is a major factor in decadal-scale variability of North Atlantic climate.

Moving East: the Euro-Lupus Nephritis regimen in Asia.

PubMed

Houssiau, Frédéric A

2016-01-01

Treatment of lupus nephritis is more evidenced-based than ever. Yet many areas of uncertainty persist. The article by Rathi et al. brings a piece to the puzzle by comparing, in a group of Indian patients, the Euro-Lupus low-dose i.v. cyclophosphamide regimen with mycophenolate mofetil. Although some caveats must be raised, the results suggest that, after crossing the Atlantic, the Euro-Lupus regimen may well be moving East. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Barriers to Gene Flow in the Marine Environment: Insights from Two Common Intertidal Limpet Species of the Atlantic and Mediterranean

PubMed Central

Sá-Pinto, Alexandra; Branco, Madalena S.; Alexandrino, Paulo B.; Fontaine, Michaël C.; Baird, Stuart J. E.

2012-01-01

Knowledge of the scale of dispersal and the mechanisms governing gene flow in marine environments remains fragmentary despite being essential for understanding evolution of marine biota and to design management plans. We use the limpets Patella ulyssiponensis and Patella rustica as models for identifying factors affecting gene flow in marine organisms across the North-East Atlantic and the Mediterranean Sea. A set of allozyme loci and a fragment of the mitochondrial gene cytochrome C oxidase subunit I were screened for genetic variation through starch gel electrophoresis and DNA sequencing, respectively. An approach combining clustering algorithms with clinal analyses was used to test for the existence of barriers to gene flow and estimate their geographic location and abruptness. Sharp breaks in the genetic composition of individuals were observed in the transitions between the Atlantic and the Mediterranean and across southern Italian shores. An additional break within the Atlantic cluster separates samples from the Alboran Sea and Atlantic African shores from those of the Iberian Atlantic shores. The geographic congruence of the genetic breaks detected in these two limpet species strongly supports the existence of transpecific barriers to gene flow in the Mediterranean Sea and Northeastern Atlantic. This leads to testable hypotheses regarding factors restricting gene flow across the study area. PMID:23239977

Effect of the tropical Pacific and Indian Ocean warming since the late 1970s on wintertime Northern Hemispheric atmospheric circulation and East Asian climate interdecadal changes

NASA Astrophysics Data System (ADS)

Chu, Cuijiao; Yang, Xiu-Qun; Sun, Xuguang; Yang, Dejian; Jiang, Yiquan; Feng, Tao; Liang, Jin

2018-04-01

Observation reveals that the tropical Pacific-Indian Ocean (TPIO) has experienced a pronounced interdecadal warming since the end of the 1970s. Meanwhile, the wintertime midlatitude Northern Hemispheric atmospheric circulation and East Asian climate have also undergone substantial interdecadal changes. The effect of the TPIO warming on these interdecadal changes are identified by a suite of AMIP-type atmospheric general circulation model experiments in which the model is integrated from September 1948 to December 1999 with prescribed historical, observed realistic sea surface temperature (SST) in a specific region and climatological SST elsewhere. Results show that the TPIO warming reproduces quite well the observed Northern Hemispheric wintertime interdecadal changes, suggesting that these interdecadal changes primarily originate from the TPIO warming. However, each sub-region of TPIO has its own distinct contribution. Comparatively, the tropical central-eastern Pacific (TCEP) and tropical western Pacific (TWP) warming makes dominant contributions to the observed positive-phase PNA-like interdecadal anomaly over the North Pacific sector, while the tropical Indian Ocean (TIO) warming tends to cancel these contributions. Meanwhile, the TIO and TWP warming makes dominant contributions to the observed positive NAO-like interdecadal anomaly over the North Atlantic sector as well as the interdecadal anomalies over the Eurasian sector, although the TWP warming's contribution is relatively small. These remote responses are directly attributed to the TPIO warming-induced tropical convection, rainfall and diabatic heating increases, in which the TIO warming has the most significant effect. Moreover, the TPIO warming excites a Gill-type pattern anomaly over the tropical western Pacific, with a low-level anticyclonic circulation anomaly over the Philippine Sea. Of three sub-regions, the TIO warming dominates such a pattern, although the TWP warming tends to cancel this effect. The anticyclonic circulation anomaly intensifies the southwesterly flow that transfers more moisture from the Bay of Bengal to East Asia and considerably increases the winter precipitation over the southern East Asia. This is strongly supported by the observational fact that there has been a significant interdecadal increase of winter precipitation over the southern China since the end of the 1970s.

Sensitivity of the Meridional Overturning Circulation to the Pattern of the Surface Density Flux

DTIC Science & Technology

2010-09-01

Atlantic alone, the Atlantic Meridional Overturning Circulation (AMOC) transports over 1015 W of heat (Ganachaud and Wunsch 2000) poleward...Phys. Oceanogr., 17, 970–985. Bryden, H. L., H. Longworth, and S. Cunningham, 2005: Slowing of the Atlantic meridional overturning circulation at 25...Rahmstorf, 2007: On the driving processes of the Atlantic meridional overturning circulation . Rev. Geophys., 45, RG2001, doi:

7 CFR 1250.510 - Determination of Board Membership.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, and the District of Columbia; Area 2 (South Atlantic States)—Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina; Area 3 (East North Central...

7 CFR 1250.510 - Determination of Board Membership.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, and the District of Columbia; Area 2 (South Atlantic States)—Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina; Area 3 (East North Central...

Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

PubMed

Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

2017-12-31

Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and temporal scales. Copyright © 2017 Elsevier B.V. All rights reserved.

Deglacial and Holocene sea-ice variability north of Iceland and response to ocean circulation changes

NASA Astrophysics Data System (ADS)

Xiao, Xiaotong; Zhao, Meixun; Knudsen, Karen Luise; Sha, Longbin; Eiríksson, Jón; Gudmundsdóttir, Esther; Jiang, Hui; Guo, Zhigang

2017-08-01

Sea-ice conditions on the North Icelandic shelf constitute a key component for the study of the climatic gradients between the Arctic and the North Atlantic Oceans at the Polar Front between the cold East Icelandic Current delivering Polar surface water and the relatively warm Irminger Current derived from the North Atlantic Current. The variability of sea ice contributes to heat reduction (albedo) and gas exchange between the ocean and the atmosphere, and further affects the deep-water formation. However, lack of long-term and high-resolution sea-ice records in the region hinders the understanding of palaeoceanographic change mechanisms during the last glacial-interglacial cycle. Here, we present a sea-ice record back to 15 ka (cal. ka BP) based on the sea-ice biomarker IP25, phytoplankton biomarker brassicasterol and terrestrial biomarker long-chain n-alkanols in piston core MD99-2272 from the North Icelandic shelf. During the Bølling/Allerød (14.7-12.9 ka), the North Icelandic shelf was characterized by extensive spring sea-ice cover linked to reduced flow of warm Atlantic Water and dominant Polar water influence, as well as strong meltwater input in the area. This pattern showed an anti-phase relationship with the ice-free/less ice conditions in marginal areas of the eastern Nordic Seas, where the Atlantic Water inflow was strong, and contributed to an enhanced deep-water formation. Prolonged sea-ice cover with occasional occurrence of seasonal sea ice prevailed during the Younger Dryas (12.9-11.7 ka) interrupted by a brief interval of enhanced Irminger Current and deposition of the Vedde Ash, as opposed to abruptly increased sea-ice conditions in the eastern Nordic Seas. The seasonal sea ice decreased gradually from the Younger Dryas to the onset of the Holocene corresponding to increasing insolation. Ice-free conditions and sea surface warming were observed for the Early Holocene, followed by expansion of sea ice during the Mid-Holocene.

Adaptive strategies and life history characteristics in a warming climate: salmon in the Arctic?

USGS Publications Warehouse

Nielsen, Jennifer L.; Ruggerone, Gregory T.; Zimmerman, Christian E.

2013-01-01

In the warming Arctic, aquatic habitats are in flux and salmon are exploring their options. Adult Pacific salmon, including sockeye (Oncorhynchus nerka), coho (O. kisutch), Chinook (O. tshawytscha), pink (O. gorbuscha) and chum (O. keta) have been captured throughout the Arctic. Pink and chum salmon are the most common species found in the Arctic today. These species are less dependent on freshwater habitats as juveniles and grow quickly in marine habitats. Putative spawning populations are rare in the North American Arctic and limited to pink salmon in drainages north of Point Hope, Alaska, chum salmon spawning rivers draining to the northwestern Beaufort Sea, and small populations of chum and pink salmon in Canada’s Mackenzie River. Pacific salmon have colonized several large river basins draining to the Kara, Laptev and East Siberian seas in the Russian Arctic. These populations probably developed from hatchery supplementation efforts in the 1960’s. Hundreds of populations of Arctic Atlantic salmon (Salmo salar) are found in Russia, Norway and Finland. Atlantic salmon have extended their range eastward as far as the Kara Sea in central Russian. A small native population of Atlantic salmon is found in Canada’s Ungava Bay. The northern tip of Quebec seems to be an Atlantic salmon migration barrier for other North American stocks. Compatibility between life history requirements and ecological conditions are prerequisite for salmon colonizing Arctic habitats. Broad-scale predictive models of climate change in the Arctic give little information about feedback processes contributing to local conditions, especially in freshwater systems. This paper reviews the recent history of salmon in the Arctic and explores various patterns of climate change that may influence range expansions and future sustainability of salmon in Arctic habitats. A summary of the research needs that will allow informed expectation of further Arctic colonization by salmon is given.

Response of North Atlantic Ocean Chlorophyll a to the Change of Atlantic Meridional Overturning Circulation

NASA Astrophysics Data System (ADS)

Zhang, Min; Zhang, Yuanling; Shu, Qi; Zhao, Chang; Wang, Gang; Wu, Zhaohua; Qiao, Fangli

2017-04-01

Changes in marine phytoplankton are a vital component in global carbon cycling. Despite this far-reaching importance, the variable trend in phytoplankton and its response to climate variability remain unclear. This work presents the spatiotemporal evolution of the chlorophyll a trend in the North Atlantic Ocean by using merged ocean color products for the period 1997-2016. We find a dipole pattern between the subpolar gyre and the Gulf Stream path,and chlorophyll a trend signal propagatedalong the opposite direction of the North Atlantic Current. Such a dipole pattern and opposite propagation of chlorophyll a signal are consistent with the recent distinctive signature of the slowdown of the Atlantic MeridionalOverturning Circulation (AMOC). It is suggested that the spatiotemporal evolution of chlorophyll a during the two most recent decades is a part of the multidecadal variation and regulated byAMOC, which could be used as an indicator of AMOC variations.

A multi-model ensemble view of winter heat flux dynamics and the dipole mode in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Liguori, Giovanni; Di Lorenzo, Emanuele; Cabos, William

2017-02-01

Changes in surface heat fluxes affect several climate processes controlling the Mediterranean climate. These include the winter formation of deep waters, which is the primary driver of the Mediterranean Sea overturning circulation. Previous studies that characterize the spatial and temporal variability of surface heat flux anomalies over the basin reveal the existence of two statistically dominant patterns of variability: a monopole of uniform sign and an east-west dipole of opposite signs. In this work, we use the 12 regional climate model ensemble from the EU-FP6 ENSEMBLES project to diagnose the large-scale atmospheric processes that control the variability of heat fluxes over the Mediterranean Sea from interannual to decadal timescales (here defined as timescales > 6 year). Our findings suggest that while the monopole structure captures variability in the winter-to-winter domain-average net heat flux, the dipole pattern tracks changes in the Mediterranean climate that are connected to the East Atlantic/Western Russia (EA/WR) atmospheric teleconnection pattern. Furthermore, while the monopole exhibits significant differences in the spatial structure across the multi-model ensemble, the dipole pattern is very robust and more clearly identifiable in the anomaly maps of individual years. A heat budget analysis of the dipole pattern reveals that changes in winds associated with the EA/WR pattern exert dominant control through both a direct effect on the latent heat flux (i.e., wind speed) and an indirect effect through specific humidity (e.g., wind advection). A simple reconstruction of the heat flux variability over the deep-water formation regions of the Gulf of Lion and the Aegean Sea reveals that the combination of the monopole and dipole time series explains over 90 % of the heat flux variance in these regions. Given the important role that surface heat flux anomalies play in deep-water formation and the regional climate, improving our knowledge on the dynamics controlling the leading modes of heat flux variability may enhance our predictability of the climate of the Mediterranean area.

Risk from drought and extreme heat in Russian wheat production and its relation to atmospheric blocking and teleconnection patterns

NASA Astrophysics Data System (ADS)

Giannakaki, Paraskevi; Calanca, Pierluigi

2017-04-01

Russia has become one of the leading wheat exporters worldwide. Major breakdowns in Russian wheat production induced by extreme weather events are therefore of high significance not only for the domestic but also for the global market. Wheat production in south-western Russia, the main growing area, suffers in particular from the adverse effects of drought and heat waves. For this reason knowledge of the occurrence of this type of extreme events and of the processes that lead to adverse conditions is of paramount importance for risk management. The negative impacts of heat waves and drought are particularly severe when anomalous conditions persist in time. As an example, a blocking event in summer 2010 resulted in one of the warmest and worst drought conditions in Russia's recent history. The latter caused a decline in Russian wheat production by more than 30%, which in turn prompted the Russian government to issue an export ban that lasted until summer 2011. In view of this, the question of course arises of how much of the negative variations in Russian wheat production levels can be explained by blocking events and other features of the large-scale atmospheric circulation. Specific questions are: how often are blocking events over Russia associated with extreme high temperatures and dry conditions? Which of the teleconnection patterns are correlated with drought and heat stress conditions in the area? Answering these questions can contribute to a develop strategies for agricultural risk management. In this contribution we present results of a study that aims at characterizing the occurrence of adverse weather conditions in south-western Russia in relation to atmospheric blocking and teleconnection patterns such as East Atlantic/Western Russia pattern, the Polar/Eurasia pattern, the North Atlantic Oscillation and the Scandinavia pattern. The analysis relies on weather data for 1980-2014 from 130 stations distributed across the wheat production area. The account for similarities in the occurrence of extreme heat, stations are clustered according to 90th percentile of daily maximum temperature. The results indicate that adverse conditions in the area are significantly correlated with the occurrence of blocking events and with the phase of some teleconnection patterns.

Variability of the Tropical Ocean Surface Temperatures at Decadal-Multidecadal Timescales. Part I: The Atlantic Ocean.

NASA Astrophysics Data System (ADS)

Mehta, Vikram M.

1998-09-01

Gridded time series from the Global Ocean Surface Temperature Atlas were analyzed with a variety of techniques to identify spatial structures and oscillation periods of the tropical Atlantic sea surface temperature (SST) variations at decadal timescales, and to develop physical interpretations of statistical patterns of decadal SST variations. Each time series was 110 yr (1882-1991) long. The tropical Atlantic SST variations were compared with decadal variations in a 74-yr-long (1912-85) north Nordeste Brazil rainfall time series and a 106-yr-long (1886-1991) tropical Atlantic cyclone activity index time series. The tropical Atlantic SST variations were also compared with decadal variations in the extratropical Atlantic SST.Multiyear to multidecadal variations in the cross-equatorial dipole pattern identified as a dominant empirical pattern of the tropical Atlantic SST variations in earlier and present studies are shown to be variations in the approximately north-south gradient of SST anomalies. It is also shown that there was no dynamical-thermodynamical, dipole mode of SST variations during the analysis period. There was a distinct decadal timescale (12-13 yr) of SST variations in the tropical South Atlantic, whereas no distinct decadal timescale was found in the tropical North Atlantic SST variations. Approximately 80% of the coherent decadal variance in the cross-equatorial SST gradient was `explained' by coherent decadal oscillations in the tropical South Atlantic SSTs. There were three, possibly physical, modes of decadal variations in the tropical Atlantic SSTs during the analysis period. In the more energetic mode of the North Atlantic decadal SST variations, anomalies traveled into the tropical North Atlantic from the extratropical North Atlantic along the eastern boundary of the basin. The anomalies strengthened and resided in the tropical North Atlantic for several years, then frequently traveled northward into the mid-high-latitude North Atlantic along the western boundary of the basin, and completed a clockwise rotation around the North Atlantic basin. In the less energetic North Atlantic decadal mode, SST anomalies originated in the tropical-subtropical North Atlantic near the African coast, and traveled northwestward and southward. In the South Atlantic decadal SST mode, anomalies either developed in situ or traveled into the tropical South Atlantic from the subtropical South Atlantic along the eastern boundary of the basin. The anomalies strengthened and resided in the tropical South Atlantic for several years, then frequently traveled southward into the subtropical South Atlantic along the western boundary of the basin, and completed a counterclockwise rotation around the South Atlantic basin. These decadal modes were not a permanent feature of the tropical Atlantic SST variations. The tropical North and South Atlantic SST anomalies frequently extended across the equator. Uncorrelated alignments of decadal SST anomalies having opposite signs on two sides of the equator occasionally created the apperance of a dipole.Independent analyses of the north Nordeste Brazil rainfall showed physical consistency and high coherence with the cross-equatorial SST gradient oscillations at 12-13-yr period. The tropical Atlantic cyclone index showed physical consistency but moderate coherence with the tropical North Atlantic decadal SST variations. The quasi-regularity of the 12-13-yr oscillations in the cross-equatorial SST gradient may provide an opportunity for long lead-time, skillful predictions of climate anomalies in the tropical Atlantic sector.

The use of satellite tags to redefine movement patterns of spiny dogfish (Squalus acanthias) along the U.S. east coast: implications for fisheries management.

PubMed

Carlson, Amy E; Hoffmayer, Eric R; Tribuzio, Cindy A; Sulikowski, James A

2014-01-01

Spiny dogfish (Squalus acanthias) are assumed to be a highly migratory species, making habitual north-south migrations throughout their northwestern Atlantic United States (U.S.) range. Also assumed to be a benthic species, spiny dogfish stock structure is estimated through Northeast Fisheries Science Center (NEFSC) bottom-trawl surveys. Recent anomalies in population trends, including a recent four-fold increase in estimated spawning stock biomass, suggest alternative movement patterns could exist for this shark species. To obtain a better understanding of the horizontal and vertical movement dynamics of this species, Microwave Telemetry pop-up satellite archival X-Tags were attached to forty adult spiny dogfish at the northern (Gulf of Maine) and southern (North Carolina) extents of their core U.S. geographic range. Reconstructed geolocation tracks ranging in lengths from two to 12 months suggest that the seasonal migration patterns appear to be local in nature to each respective northern and southern deployment site, differing from previously published migration paradigms. Differences in distance and direction traveled between seasonal geolocations possibly indicate separate migratory patterns between groups. Kernel utilization distribution models also suggest strong separate core home ranges. Significant differences in seasonal temperature and depths between the two regions further substantiate the possibility of separate regional movement patterns between the two groups. Vertical utilization also suggests distinct diel patterns and that this species may not utilize the benthos as previously thought, potentially decreasing availability to benthic gear.

The Use of Satellite Tags to Redefine Movement Patterns of Spiny Dogfish (Squalus acanthias) along the U.S. East Coast: Implications for Fisheries Management

PubMed Central

Carlson, Amy E.; Hoffmayer, Eric R.; Tribuzio, Cindy A.; Sulikowski, James A.

2014-01-01

Spiny dogfish (Squalus acanthias) are assumed to be a highly migratory species, making habitual north-south migrations throughout their northwestern Atlantic United States (U.S.) range. Also assumed to be a benthic species, spiny dogfish stock structure is estimated through Northeast Fisheries Science Center (NEFSC) bottom-trawl surveys. Recent anomalies in population trends, including a recent four-fold increase in estimated spawning stock biomass, suggest alternative movement patterns could exist for this shark species. To obtain a better understanding of the horizontal and vertical movement dynamics of this species, Microwave Telemetry pop-up satellite archival X-Tags were attached to forty adult spiny dogfish at the northern (Gulf of Maine) and southern (North Carolina) extents of their core U.S. geographic range. Reconstructed geolocation tracks ranging in lengths from two to 12 months suggest that the seasonal migration patterns appear to be local in nature to each respective northern and southern deployment site, differing from previously published migration paradigms. Differences in distance and direction traveled between seasonal geolocations possibly indicate separate migratory patterns between groups. Kernel utilization distribution models also suggest strong separate core home ranges. Significant differences in seasonal temperature and depths between the two regions further substantiate the possibility of separate regional movement patterns between the two groups. Vertical utilization also suggests distinct diel patterns and that this species may not utilize the benthos as previously thought, potentially decreasing availability to benthic gear. PMID:25068584

Timber harvesting patterns for major states in the central, northern, and mid-Atlantic hardwood regions

Treesearch

William G. Luppold; Matthew S. Bumgardner

2018-01-01

Timber harvesting is a major disturbance agent influencing the composition and structure of eastern hardwood forests. To better understand timber harvesting practices, we examined roundwood harvesting patterns in 13 eastern states in the Central, Mid-Atlantic, and Northern regions that contained high proportional volumes of hardwood in their forest inventories. Nearly...

Multilocus Bayesian Estimates of Intra-Oceanic Genetic Differentiation, Connectivity, and Admixture in Atlantic Swordfish (Xiphias gladius L.)

PubMed Central

Smith, Brad L.; Lu, Ching-Ping; García-Cortés, Blanca; Viñas, Jordi; Yeh, Shean-Ya; Alvarado Bremer, Jaime R.

2015-01-01

Previous genetic studies of Atlantic swordfish (Xiphias gladius L.) revealed significant differentiation among Mediterranean, North Atlantic and South Atlantic populations using both mitochondrial and nuclear DNA data. However, limitations in geographic sampling coverage, and the use of single loci, precluded an accurate placement of boundaries and of estimates of admixture. In this study, we present multilocus analyses of 26 single nucleotide polymorphisms (SNPs) within 10 nuclear genes to estimate population differentiation and admixture based on the characterization of 774 individuals representing North Atlantic, South Atlantic, and Mediterranean swordfish populations. Pairwise F ST values, AMOVA, PCoA, and Bayesian individual assignments support the differentiation of swordfish inhabiting these three basins, but not the current placement of the boundaries that separate them. Specifically, the range of the South Atlantic population extends beyond 5°N management boundary to 20°N-25°N from 45°W. Likewise the Mediterranean population extends beyond the current management boundary at the Strait of Gibraltar to approximately 10°W. Further, admixture zones, characterized by asymmetric contributions of adjacent populations within samples, are confined to the Northeast Atlantic. While South Atlantic and Mediterranean migrants were identified within these Northeast Atlantic admixture zones no North Atlantic migrants were identified respectively in these two neighboring basins. Owing to both, the characterization of larger number of loci and a more ample spatial sampling coverage, it was possible to provide a finer resolution of the boundaries separating Atlantic swordfish populations than previous studies. Finally, the patterns of population structure and admixture are discussed in the light of the reproductive biology, the known patterns of dispersal, and oceanographic features that may act as barriers to gene flow to Atlantic swordfish. PMID:26057382

Dissolved organic sulfur in the ocean: Biogeochemistry of a petagram inventory

NASA Astrophysics Data System (ADS)

Ksionzek, Kerstin B.; Lechtenfeld, Oliver J.; McCallister, S. Leigh; Schmitt-Kopplin, Philippe; Geuer, Jana K.; Geibert, Walter; Koch, Boris P.

2016-10-01

Although sulfur is an essential element for marine primary production and critical for climate processes, little is known about the oceanic pool of nonvolatile dissolved organic sulfur (DOS). We present a basin-scale distribution of solid-phase extractable DOS in the East Atlantic Ocean and the Atlantic sector of the Southern Ocean. Although molar DOS versus dissolved organic nitrogen (DON) ratios of 0.11 ± 0.024 in Atlantic surface water resembled phytoplankton stoichiometry (sulfur/nitrogen ~ 0.08), increasing dissolved organic carbon (DOC) versus DOS ratios and decreasing methionine-S yield demonstrated selective DOS removal and active involvement in marine biogeochemical cycles. Based on stoichiometric estimates, the minimum global inventory of marine DOS is 6.7 petagrams of sulfur, exceeding all other marine organic sulfur reservoirs by an order of magnitude.

Interannual Variation of Sea Level in the South Atlantic Based on Satellite Altimetry

NASA Astrophysics Data System (ADS)

Grodsky, S. A.; Carton, J. A.

2006-07-01

13 years of altimeter month ly sea level ar e used to explore interannual variability of the South Atlantic. The strongest v ariability outside the eastern and western boundaries is conf ined to a relatively narrow zonally oriented band b etw een 35°S and 25°S, the Agulhas eddy corridor. On th eir way across th e South Atlantic th e Agulh as eddies g ain energy on the southern flank of the eddy corridor via baro tropic conversions by deceler ating the South Atlan tic Curren t. On interannual time scales the sea level in the corridor fluctu ates out of phase in the w est and east r evealing noticeab le v ariations of 10 cm amp litude at 4 to 5 year periods.

Impacts of Tropical North Atlantic SST on Western North Pacific Landfalling Tropical Cyclones

NASA Astrophysics Data System (ADS)

Zhang, W.; Gao, S.; Chen, Z.

2017-12-01

This study examines the impacts of tropical North Atlantic (TNA) sea surface temperature (SST) anomaly (SSTA) on tropical cyclones (TCs) making landfall over East Asia. We find that TNA SSTA has significant negative correlations with the frequency of TCs making landfall over China, Vietnam, Korea and Japan, and the entire East Asia. TNA SST influences the frequency of TC landfalls over these regions by regulating TC genesis location and frequency and steering flow associated with modulated environmental conditions. During cold TNA SST years, larger low-level relative vorticity and weaker vertical wind shear lead to more TC formations in the northern SCS and to the east of Philippines, and larger low-level relative vorticity, higher mid-level relative humidity, and weaker vertical wind shear result in more TC formations over the eastern part of WNP. Anomalous northeasterly steering flow favors more TCs to move westward or west-northwestward and make landfall over Vietnam, South China and Taiwan Island and thus in the entire China, and more TCs take regular northeastward recurving tracks and make landfall over Korea and Japan because of insignificant steering flow anomalies in the vicinity. The modulation of large-scale environments by TNA SSTA may be through two possible pathways proposed in previous studies, i.e., Indian Ocean relaying effect and subtropical eastern Pacific relaying effect. Our results suggest that TNA SSTA is a potential predictor for the frequency of TCs making landfall over China, Vietnam, Korea and Japan, and the entire East Asia.

Transcription expression of immune-related genes from Caligus rogercresseyi evidences host-dependent patterns on Atlantic and coho salmon.

PubMed

Vera-Bizama, Fredy; Valenzuela-Muñoz, Valentina; Gonçalves, Ana Teresa; Marambio, Jorge Pino; Hawes, Christopher; Wadsworth, Simon; Gallardo-Escárate, Cristian

2015-12-01

The transcriptomic response of the sea louse Caligus rogercresseyi during the infestation on Atlantic salmon (Salmo salar) and coho salmon (Oncorhynchus kisutch) was evaluated using 27 genes related to immune response, antioxidant system and secretome. Results showed early responses of TLR/IMD signaling pathway in sea lice infesting Atlantic salmon. Overall, genes associated with oxidative stress responses were upregulated in both host species. This pattern suggests that reactive oxygen species emitted by the host as a response to the infestation, could modulate the sea louse antioxidant system. Secretome-related transcripts evidenced upregulation of trypsins and serpins, mainly associated to Atlantic salmon than coho salmon. Interestingly, cathepsins and trypsin2 were downregulated at 7 days post-infection (dpi) in coho salmon. The principal component analysis revealed an inverse time-dependent pattern based on the different responses of C. rogercresseyi infecting both salmon species. Here, Atlantic salmon strongly modulates the transcriptome responses at earlier infection stages; meanwhile coho salmon reveals a less marked modulation, increasing the transcription activity during the infection process. This study evidences transcriptome differences between two salmon host species and provides pivotal knowledge towards elaborating future control strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Organohalogen contaminants and trace metals in North-East Atlantic porbeagle shark (Lamna nasus).

PubMed

Bendall, Victoria A; Barber, Jonathan L; Papachlimitzou, Alexandra; Bolam, Thi; Warford, Lee; Hetherington, Stuart J; Silva, Joana F; McCully, Sophy R; Losada, Sara; Maes, Thomas; Ellis, Jim R; Law, Robin J

2014-08-15

The North-East Atlantic porbeagle (Lamna nasus) population has declined dramatically over the last few decades and is currently classified as 'Critically Endangered'. As long-lived, apex predators, they may be vulnerable to bioaccumulation of contaminants. In this study organohalogen compounds and trace elements were analysed in 12 specimens caught as incidental bycatch in commercial gillnet fisheries in the Celtic Sea in 2011. Levels of organohalogen contaminants were low or undetectable (summed CB and BDE concentrations 0.04-0.85 mg kg(-1)wet weight). A notably high Cd concentration (7.2 mg kg(-1)wet weight) was observed in one mature male, whereas the range observed in the other samples was much lower (0.04-0.26 mg kg(-1)wet weight). Hg and Pb concentrations were detected only in single animals, at 0.34 and 0.08 mg kg(-1)wet weight, respectively. These contaminant levels were low in comparison to other published studies for shark species. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

A multi-criteria evaluation system for marine litter pollution based on statistical analyses of OSPAR beach litter monitoring time series.

PubMed

Schulz, Marcus; Neumann, Daniel; Fleet, David M; Matthies, Michael

2013-12-01

During the last decades, marine pollution with anthropogenic litter has become a worldwide major environmental concern. Standardized monitoring of litter since 2001 on 78 beaches selected within the framework of the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) has been used to identify temporal trends of marine litter. Based on statistical analyses of this dataset a two-part multi-criteria evaluation system for beach litter pollution of the North-East Atlantic and the North Sea is proposed. Canonical correlation analyses, linear regression analyses, and non-parametric analyses of variance were used to identify different temporal trends. A classification of beaches was derived from cluster analyses and served to define different states of beach quality according to abundances of 17 input variables. The evaluation system is easily applicable and relies on the above-mentioned classification and on significant temporal trends implied by significant rank correlations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Global warming hiatus contributed to the increased occurrence of intense tropical cyclones in the coastal regions along East Asia.

PubMed

Zhao, Jiuwei; Zhan, Ruifen; Wang, Yuqing

2018-04-16

The recent global warming hiatus (GWH) was characterized by a La Niña-like cooling in the tropical Eastern Pacific accompanied with the Indian Ocean and the tropical Atlantic Ocean warming. Here we show that the recent GWH contributed significantly to the increased occurrence of intense tropical cyclones in the coastal regions along East Asia since 1998. The GWH associated sea surface temperature anomalies triggered a pair of anomalous cyclonic and anticyclonic circulations and equatorial easterly anomalies over the Northwest Pacific, which favored TC genesis and intensification over the western Northwest Pacific but suppressed TC genesis and intensification over the southeastern Northwest Pacific due to increased vertical wind shear and anticyclonic circulation anomalies. Results from atmospheric general circulation model experiments demonstrate that the Pacific La Niña-like cooling dominated the Indian Ocean and the tropical Atlantic Ocean warming in contributing to the observed GWH-related anomalous atmospheric circulation over the Northwest Pacific.

Role of Seasonal Transitions and Westerly Jets in East Asian Paleoclimate

NASA Astrophysics Data System (ADS)

Chiang, J. C. H.; Fung, I. Y.; Wu, C. H.; Cai, Y.; Edman, J. P.; Liu, Y.; Day, J. A.; Bhattacharya, T.; Mondal, Y.; Labrousse, C.

2014-12-01

The summer rainfall climate of East Asia underwent large and abrupt changes in response to precessional forcing, glacial-interglacial cycles as well as abrupt changes to the North Atlantic during the last glacial. Current interpretations of said changes are typically formulated in terms of modulation of summer monsoon intensity, and do not account for the known complexity in the seasonal evolution of East Asian rainfall, which exhibits sharp transition from the Spring regime to the Meiyu, and then again from the Meiyu to the summertime. We explore the interpretation that East Asian rainfall climate undergoes a modulation of its seasonality during said paleoclimate changes. Following previous suggestions, we focus on role of the westerly jet: namely that the latitude of this westerly jet relative to Tibet is critical in determining the stepwise transitions in East Asian rainfall seasons. In support of this linkage, we show evidence from observational data for such a linkage in the timing of the Meiyu and Summer transitions, with more northward-shifted westerlies associated with earlier transitions. We similarly suggest that East Asian paleoclimate changes resulted from an altered timing in the northward evolution of the jet and hence the seasonal transitions, in particular the transition of the jet from south of the Plateau to the north that determines the seasonal transition from Spring rains to the Meiyu. In an extreme scenario - which we speculate the climate system tended towards during stadial (cold) phases of D/O stadials and periods of low Northern Hemisphere summer insolation - the jet does not jump north of the Plateau, essentially keeping East Asia in prolonged Spring conditions. We show that this hypothesis can explain a key paleoproxy signature of D/O stadials over East Asia, namely the heavier mean δ18O of precipitation as recorded in speleothem records. The southward jet position prevents the low-level monsoonal flow - which is isotopically light - from penetrating into the interior of East Asia; as such, precipitation there will be heavier, consistent with speleothem records. This hypothesis can also explain other key evidences of East Asian paleoclimate changes, in particular the occurrence of dusty conditions during North Atlantic stadials, and the southward migration of the Holocene optimal rainfall.

Increasing magnitude of Hurricane Rapid Intensification in the central-eastern Atlantic over the past 30 years

NASA Astrophysics Data System (ADS)

Leung, L. R.; Balaguru, K.; Foltz, G. R.

2017-12-01

During the 2017 Atlantic hurricane season, several hurricanes underwent rapid intensification (RI) in the central-eastern Atlantic. This motivates an analysis of trends in the strength of hurricane RI during the 30-year post-satellite period of 1986-2015. Our results show that in the eastern tropical Atlantic, to the east of 60W, the mean RI magnitude averaged during 2001-2015 was 3.8 kt per 24 hr higher than during 1986-2000. However, in the western tropical Atlantic, to the west of 60W, changes in RI magnitude over the same period were not statistically significant. We examined the large-scale environment to understand the causes behind these changes in RI magnitude and found that various oceanic and atmospheric parameters that play an important role in RI changed favorably in the eastern tropical Atlantic. More specifically, changes in SST, Potential Intensity, upper-ocean heat content, wind shear, relative humidity and upper-level divergence enhanced the ability for hurricanes to undergo RI in the eastern tropical Atlantic. In contrast, changes in the same factors are inconsistent in the western tropical Atlantic. While changes in SST and Potential Intensity were positive, changes in upper-ocean heat content, wind shear and upper-level divergence were either insignificant or unfavorable for RI. Finally, we examined the potential role of various climate phenomena, which are well-known to impact Atlantic hurricane activity, in causing the changes in the large-scale environment. Our analysis reveals that changes in the Atlantic Multidecadal Oscillation over the 30-year period are predominantly responsible. These results provide important aspects of the large-scale context to understand the Atlantic hurricane season of 2017.

Large-scale circulation classification and its links to observed precipitation in the eastern and central Tibetan Plateau

NASA Astrophysics Data System (ADS)

Liu, Wenbin; Wang, Lei; Chen, Deliang; Tu, Kai; Ruan, Chengqing; Hu, Zengyun

2016-06-01

The relationship between the large-scale circulation dynamics and regional precipitation regime in the Tibetan Plateau (TP) has so far not been well understood. In this study, we classify the circulation types using the self-organizing maps based on the daily field of 500 hPa geopotential height and link them to the precipitation climatology in the eastern and central TP. By virtue of an objective determining method, 18 circulation types are quantified. The results show that the large amount of precipitation in summer is closely related to the circulation types in which the enhanced and northward shifted subtropical high (SH) over the northwest Pacific and the obvious cyclconic circulation anomaly over the Bay of Bengal are helpful for the Indian summer monsoon and East Asian summer monsoon to take abundant low-latitude moisture to the eastern and southern TP. On the contrary, the dry winter in the central and eastern Tibet corresponds to the circulation types with divergence over the central and eastern TP and the water vapor transportations of East Asian winter monsoon and mid-latitude westerly are very weak. Some circulation types are associated with some well-known circulation patterns/monsoons influencing the TP (e.g. East Atlantic Pattern, El Niño Southern Oscillation, Indian Summer Monsoon and the mid-latitude westerly), and exhibit an overall good potential for explaining the variability of regional seasonal precipitation. Moreover, the climate shift signals in the late 1970s over the eastern Pacific/North Pacific Oceans could also be reflected by both the variability of some circulation types and their correspondingly composite precipitations. This study extends our understandings for the large-scale atmospheric dynamics and their linkages with regional precipitation and is beneficial for the climate change projection and related adaptation activities in the highest and largest plateau in the world.

Changes in Greenland's peripheral glaciers linked to the North Atlantic Oscillation

NASA Astrophysics Data System (ADS)

Bjørk, A. A.; Aagaard, S.; Lütt, A.; Khan, S. A.; Box, J. E.; Kjeldsen, K. K.; Larsen, N. K.; Korsgaard, N. J.; Cappelen, J.; Colgan, W. T.; Machguth, H.; Andresen, C. S.; Peings, Y.; Kjær, K. H.

2018-01-01

Glaciers and ice caps peripheral to the main Greenland Ice Sheet contribute markedly to sea-level rise1-3. Their changes and variability, however, have been difficult to quantify on multi-decadal timescales due to an absence of long-term data4. Here, using historical aerial surveys, expedition photographs, spy satellite imagery and new remote-sensing products, we map glacier length fluctuations of approximately 350 peripheral glaciers and ice caps in East and West Greenland since 1890. Peripheral glaciers are found to have recently undergone a widespread and significant retreat at rates of 12.2 m per year and 16.6 m per year in East and West Greenland, respectively; these changes are exceeded in severity only by the early twentieth century post-Little-Ice-Age retreat. Regional changes in ice volume, as reflected by glacier length, are further shown to be related to changes in precipitation associated with the North Atlantic Oscillation (NAO), with a distinct east-west asymmetry; positive phases of the NAO increase accumulation, and thereby glacier growth, in the eastern periphery, whereas opposite effects are observed in the western periphery. Thus, with projected trends towards positive NAO in the future5,6, eastern peripheral glaciers may remain relatively stable, while western peripheral glaciers will continue to diminish.

Tsunami Inundation Mapping for the Upper East Coast of the United States

NASA Astrophysics Data System (ADS)

Tehranirad, B.; Kirby, J. T., Jr.; Callahan, J. A.; Shi, F.; Banihashemi, S.; Grilli, S. T.; Grilli, A. R.; Tajalli Bakhsh, T. S.; O'Reilly, C.

2014-12-01

We describe the modeling of tsunami inundation for the Upper US East Coast (USEC) from Ocean City, MD up to Nantucket, MA. and the development of inundation maps for use in emergency management and hazard analysis. Seven tsunami sources were used as initial conditions in order to develop inundation maps based on a Probable Maximum Tsunami approach. Of the seven, two coseismic sources were used; the first being a large earthquake in the Puerto Rico Trench, in the well-known Caribbean Subduction Zone, and the second, an earthquake close to the Azores Gibraltar plate boundary known as the source of the biggest tsunami recorded in the North Atlantic Basin. In addition, four Submarine Mass Failure (SMF) sources located at different locations on the edge of the shelf break were simulated. Finally, the Cumbre Vieja Volcanic (CVV) collapse, located in the Canary Islands, was studied. For this presentation, we discuss modeling results for nearshore tsunami propagation and onshore inundation. A fully nonlinear Boussinesq model (FUNWAVE-TVD) is used to capture the characteristics of tsunami propagation, both nearshore and inland. In addition to the inundation line as the main result of this work, other tsunami quantities such as inundation depth and maximum velocities will be discussed for the whole USEC area. Moreover, a discussion of most vulnerable areas to a possible tsunami in the USEC will be provided. For example, during the inundation simulation process, it was observed that coastal environments with barrier islands are among the hot spots to be significantly impacted by a tsunami. As a result, areas like western Long Island, NY and Atlantic City, NJ are some of the locations that will get extremely affected in case of a tsunami occurrence in the Atlantic Ocean. Finally, the differences between various tsunami sources modeled here will be presented. Although inundation lines for different sources usually follow a similar pattern, there are clear distinctions between the inundation depth and other tsunami features in different areas. Figure below shows the inundation depth for surrounding area of the Ocean City, MD. Figure (a) and (b) are the envelope inundation depth for SMF and coseismic sources. Figure (C) shows the inundation depth for CVV source, which clearly has the largest magnitude amongst the sources studied for this work.

Climatic variability of river outflow in the Pantanal region and the influence of sea surface temperature

NASA Astrophysics Data System (ADS)

Silva, Carlos Batista; Silva, Maria Elisa Siqueira; Ambrizzi, Tércio

2017-07-01

This paper investigates possible linear relationships between climate, hydrology, and oceanic surface variability in the Pantanal region (in South America's central area), over interannual and interdecadal time ranges. In order to verify the mentioned relations, lagged correlation analysis and linear adjustment between river discharge at the Pantanal region and sea surface temperature were used. Composite analysis for atmospheric fields, air humidity flux divergence, and atmospheric circulation at low and high levels, for the period between 1970 and 2003, was analyzed. Results suggest that the river discharge in the Pantanal region is linearly associated with interdecadal and interannual oscillations in the Pacific and Atlantic oceans, making them good predictors to continental hydrological variables. Considering oceanic areas, 51 % of the annual discharge in the Pantanal region can be linearly explained by mean sea surface temperature (SST) in the Subtropical North Pacific, Tropical North Pacific, Extratropical South Pacific, and Extratropical North Atlantic over the period. Considering a forecast approach in seasonal scale, 66 % of the monthly discharge variance in Pantanal, 3 months ahead of SST, is explained by the oceanic variables, providing accuracy around 65 %. Annual discharge values in the Pantanal region are strongly related to the Pacific Decadal Oscillation (PDO) variability (with 52 % of linear correlation), making it possible to consider an interdecadal variability and a consequent subdivision of the whole period in three parts: 1st (1970-1977), 2nd (1978-1996), and 3rd (1997-2003) subperiods. The three subperiods coincide with distinct PDO phases: negative, positive, and negative, respectively. Convergence of humidity flux at low levels and the circulation pattern at high levels help to explain the drier and wetter subperiods. During the wetter 2nd subperiod, the air humidity convergence at low levels is much more evident than during the other two drier subperiods, which mostly show air humidity divergence. While the drier periods are particularly characterized by the strengthening of northerly wind over the center of South America, including the Pantanal region, the wetter period is characterized by its weakening. The circulation pattern at 850 hPa levels during the drier subperiods shows anticyclonic anomalies centered over east central South America. Also, the drier subperiods (1st and 3rd) are characterized by negative stream function anomalies over southeastern South America and adjacent South Atlantic, and the wetter subperiod is characterized by positive stream function anomalies. In the three subperiods, one can see mean atmospheric patterns associated with Rossby wave propagation coming from the South Pacific basin—similar to the Pacific South America pattern, but with reverse signals between the wetter and the drier periods. This result suggests a possible relationship between climatic patterns over southeastern South America regions and the Pacific conditions in a decadal scale.

Impacts of the EA and SCA patterns on the 20th century NAO-winter precipitation relationship in Europe

NASA Astrophysics Data System (ADS)

Comas-Bru, Laia; McDermott, Frank

2013-04-01

Much of the 20th century multi-decadal variability in the NAO-winter precipitation relationship over the N. Atlantic / European sector can be ascribed to the combined effects of the North Atlantic Oscillation (NAO) and either the East Atlantic pattern (EA) or the Scandinavian pattern (SCA). The NAO, EA and SCA indices employed here are defined as the three leading vectors of the cross-correlation matrix calculated from monthly sea-level pressure anomalies for 138 complete winters from the 20CRv2 dataset (Compo et al., 2011). Winter precipitation data over Europe for the entire 20th century is derived from the high resolution CRU-TS3.1 climate dataset (Mitchell and Jones, 2005). Here we document for the first time, that different NAO/EA and NAO/SCA combinations systematically influence winter precipitation conditions in Europe as a consequence of NAO dipole migrations. We find that the zero-correlated line of the NAO-winter precipitation relationship migrates southwards when the EA is in the opposite phase to the NAO. This can be related to a south-westwards migration of the NAO dipole under these conditions, as shown by teleconnectivity maps. Similarly, a clockwise movement of the NAO-winter climate correlated areas occurs when the phase of the SCA is opposite to that of the NAO, reflecting a clockwise movement of the NAO dipole under these conditions. An important implication of these migrations is that they influence the spatial and temporal stationarity of climate-NAO relationships. As a result, the link between winter precipitation patterns and the NAO is not straightforward in some regions such as the southern UK, Ireland and France. For instance, much of the inter-annual variability in the N-S winter precipitation gradient in the UK, originally attributed to inter-annual and inter-decadal variability of the NAO, reflects the migration of the NAO dipole, linked to linear combinations of the NAO and the EA. Our results indicate that when the N-S winter precipitation gradient is accentuated by the occurrence of a positive EA during positive NAO winters, drier conditions than normal are found in the southern UK. This is consistent, for example, with the severe winter drought of 1976, when computed NAO and EA indices were both positive (0.97 and 1.87, respectively), illustrating the modulating effect of NAO/EA combinations on winter precipitation patterns in the southern UK. References: Compo GP et al. 2011. The Twentieth Century Reanalysis Project. Quarterly Journal of the Royal Meteorological Society, 137 (654), 1-28. Mitchell TD, Jones PD. 2005. An improved method for constructing a database of monthly climate observations and associated high-resolution grids. International Journal of Climatology, 25, 693-712.

77 FR 74612 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-17

... Atlantic tunas General category BFT daily retention limit to two large medium or giant BFT for the January... might be exceeded; effects of the adjustment on BFT rebuilding and overfishing; effects of the... distribution, abundance, or migration patterns of BFT; effects of catch rates in one area precluding vessels in...

Glacier maxima in Baffin Bay during the Medieval Warm Period coeval with Norse settlement

PubMed Central

Young, Nicolás E.; Schweinsberg, Avriel D.; Briner, Jason P.; Schaefer, Joerg M.

2015-01-01

The climatic mechanisms driving the shift from the Medieval Warm Period (MWP) to the Little Ice Age (LIA) in the North Atlantic region are debated. We use cosmogenic beryllium-10 dating to develop a moraine chronology with century-scale resolution over the last millennium and show that alpine glaciers in Baffin Island and western Greenland were at or near their maximum LIA configurations during the proposed general timing of the MWP. Complimentary paleoclimate proxy data suggest that the western North Atlantic region remained cool, whereas the eastern North Atlantic region was comparatively warmer during the MWP—a dipole pattern compatible with a persistent positive phase of the North Atlantic Oscillation. These results demonstrate that over the last millennium, glaciers approached their eventual LIA maxima before what is considered the classic LIA in the Northern Hemisphere. Furthermore, a relatively cool western North Atlantic region during the MWP has implications for understanding Norse migration patterns during the MWP. Our results, paired with other regional climate records, point to nonclimatic factors as contributing to the Norse exodus from the western North Atlantic region. PMID:26665173

Sensitivity of the regional climate in the Middle East and North Africa to volcanic perturbations

NASA Astrophysics Data System (ADS)

Dogar, Muhammad Mubashar; Stenchikov, Georgiy; Osipov, Sergey; Wyman, Bruce; Zhao, Ming

2017-08-01

The Middle East and North Africa (MENA) regional climate appears to be extremely sensitive to volcanic eruptions. Winter cooling after the 1991 Pinatubo eruption far exceeded the mean hemispheric temperature anomaly, even causing snowfall in Israel. To better understand MENA climate variability, the climate responses to the El Chichón and Pinatubo volcanic eruptions are analyzed using observations, NOAA/National Centers for Environmental Prediction Climate Forecast System Reanalysis, and output from the Geophysical Fluid Dynamics Laboratory's High-Resolution Atmospheric Model. A multiple regression analysis both for the observations and the model output is performed on seasonal summer and winter composites to separate out the contributions from climate trends, El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian summer monsoon, and volcanic aerosols. Strong regional temperature and precipitation responses over the MENA region are found in both winter and summer. The model and the observations both show that a positive NAO amplifies the MENA volcanic winter cooling. In boreal summer, the patterns of changing temperature and precipitation suggest a weakening and southward shift of the Intertropical Convergence Zone, caused by volcanic surface cooling and weakening of the Indian and West African monsoons. The model captures the main features of the climate response; however, it underestimates the total cooling, especially in winter, and exhibits a different spatial pattern of the NAO climate response in MENA compared to the observations. The conducted analysis sheds light on the internal mechanisms of MENA climate variability and helps to selectively diagnose the model deficiencies.

Natural versus anthropogenic factors affecting low-level cloud albedo over the North Atlantic

NASA Technical Reports Server (NTRS)

Falkowski, Paul G.; Kim, Yongseung; Kolber, Zbigniew; Wilson, Cara; Wirick, Creighton; Cess, Robert

1992-01-01

Cloud albedo plays a key role in regulating earth's climate. Cloud albedo depends on column-integrated liquid water content and the density of cloud condensation nuclei, which consists primarily of submicrometer-sized aerosol sulfate particles. A comparison of two independent satellite data sets suggests that, although anthropogenic sulfate emissions may enhance cloud albedo immediately adjacent to the east coast of the United States, over the central North Atlantic Ocean the variability in albedo can be largely accounted for by natural marine and atmospheric processes that probably have remained relatively constant since the beginning of the industrial revolution.

Aerosol-radiation-cloud interactions in the South-East Atlantic: first results from the ORACLES-2016 deployment and plans for future activities

NASA Astrophysics Data System (ADS)

Redemann, J.; Wood, R.; Zuidema, P.; Haywood, J. M.; Piketh, S.; Formenti, P.; Abel, S.

2016-12-01

Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles. Particles lofted into the mid-troposphere are transported westward over the South-East (SE) Atlantic, home to one of the three permanent subtropical stratocumulus (Sc) cloud decks in the world. The SE Atlantic stratocumulus deck interacts with the dense layers of BB aerosols that initially overlay the cloud deck, but later subside and may mix into the clouds. These interactions include adjustments to aerosol-induced solar heating and microphysical effects, and their global representation in climate models remains one of the largest uncertainties in estimates of future climate. Hence, new observations over the SE Atlantic have significant implications for regional and global climate change predictions. Our understanding of aerosol-cloud interactions in the SE Atlantic is severely limited. Most notably, we are missing knowledge on the absorptive and cloud nucleating properties of aerosols, including their vertical distribution relative to clouds, on the locations and degree of aerosol mixing into clouds, on the processes that govern cloud property adjustments, and on the importance of aerosol effects on clouds relative to co-varying synoptic scale meteorology. We describe first results from various synergistic, international research activities aimed at studying aerosol-cloud interactions in the region: NASA's airborne ORACLES (ObseRvations of Aerosols Above Clouds and Their IntEractionS) deployment in August/September of 2016, the DoE's LASIC (Layered Atlantic Smoke Interactions with Clouds) deployment of the ARM Mobile Facility to Ascension Island (June 2016 - October 2017), the ground-based components of CNRS' AEROCLO-sA (Aerosols Clouds and Fog over the west coast of southern Africa), and ongoing regional-scale integrative, process-oriented science efforts as part of SEALS-sA (Sea Earth Atmosphere Linkages Study in southern Africa). We expect to describe experimental setups as well as showcase initial aerosol and cloud property distributions. Furthermore, we discuss the implementation of future activities in these programs in coordination with the UK Met Office's CLARIFY (CLoud-Aerosol-Radiation Interactions and Forcing) experiment in 2017.

Aerosol-Cloud Interactions in the South-East Atlantic: Knowledge Gaps, Planned Observations to Address Them, and Implications for Global Climate Change Modeling

NASA Technical Reports Server (NTRS)

Redemann, Jens; Wood, R.; Zuidema, P.; Haywood, J.; Luna, B.; Abel, S.

2015-01-01

Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles, yet the fate of these particles and their influence on regional and global climate is poorly understood. Particles lofted into the mid-troposphere are transported westward over the South-East (SE) Atlantic, home to one of the three permanent subtropical Stratocumulus (Sc) cloud decks in the world. The stratocumulus "climate radiators" are critical to the regional and global climate system. They interact with dense layers of BB aerosols that initially overlay the cloud deck, but later subside and are mixed into the clouds. These interactions include adjustments to aerosol-induced solar heating and microphysical effects. As emphasized in the latest IPCC report, the global representation of these aerosol-cloud interaction processes in climate models is one of the largest uncertainty in estimates of future climate. Hence, new observations over the SE Atlantic have significant implications for global climate change scenarios. We discuss the current knowledge of aerosol and cloud property distributions based on satellite observations and sparse suborbital sampling, and describe planned field campaigns in the region. Specifically, we describe the scientific objectives and implementation of the following four synergistic, international research activities aimed at providing a process-level understanding of aerosol-cloud interactions over the SE Atlantic: 1) ORACLES (Observations of Aerosols above Clouds and their interactions), a five-year investigation between 2015 and 2019 with three Intensive Observation Periods (IOP), recently funded by the NASA Earth-Venture Suborbital Program, 2) CLARIFY-2016 (Cloud-Aerosol-Radiation Interactions and Forcing: Year 2016), a comprehensive observational and modeling programme funded by the UK's Natural Environment Research Council (NERC), and supported by the UK Met Office. 3) LASIC (Layered Atlantic Smoke Interactions with Clouds), a funded deployment of the DOE (Department of Energy) ARM Mobile Facility (AMF1) to Ascension Island, nominally for April 1 2016 - March 31 2017, and 4) ONFIRE (Observations of Fire's Impact on the southeast Atlantic Region), a proposed deployment of the NCAR C-130 aircraft to Sao Tome Island in 2017.

150 YEARS OF SALMON RESTORATION: ASSORTED TRUTHS

EPA Science Inventory

Billions of dollars have been spent in a so-far failed attempt to reverse the long-term decline of wild Pacific salmon. Of the Earth's four regions (i.e., Asian Far East, Atlantic Europe, eastern North America, and western North America) where salmon runs originally occurred, it...

SALMON RECOVERY: LEARNING FROM SUCCESSES AND MISTAKES

EPA Science Inventory

Billions of dollars have been spent in a so-far failed attempt to reverse the long-term decline of wild Pacific salmon. Of the Earth's four regions (i.e., Asian Far East, Atlantic Europe, eastern North America, and western North America) where salmon runs occurred originally, it...

SALMON RECOVERY: LEARNING FROM SUCCESSES AND FAILURES

EPA Science Inventory

Billions of dollars have been spent in a so-far failed attempt to reverse the long-term decline of wild Pacific salmon. Of the Earth's four regions (i.e., Asian Far East, Atlantic Europe, eastern North America, and western North America) where salmon runs occurred originally, it...

33 CFR 167.150 - Off New York Traffic Separation Scheme: General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Scheme: General. 167.150 Section 167.150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.150 Off New York Traffic...

33 CFR 167.151 - Off New York: Precautionary areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.151 Off New York: Precautionary areas. (a) A.... (b) A precautionary area is established between the traffic separation scheme “Eastern Approach, off...

33 CFR 167.170 - Off Delaware Bay Approach Traffic Separation Scheme: General.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Separation Scheme: General. 167.170 Section 167.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.170 Off Delaware...

33 CFR 167.170 - Off Delaware Bay Approach Traffic Separation Scheme: General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Separation Scheme: General. 167.170 Section 167.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.170 Off Delaware...

33 CFR 167.151 - Off New York: Precautionary areas.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.151 Off New York: Precautionary areas. (a) A.... (b) A precautionary area is established between the traffic separation scheme “Eastern Approach, off...

33 CFR 167.150 - Off New York Traffic Separation Scheme: General.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Scheme: General. 167.150 Section 167.150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.150 Off New York Traffic...

33 CFR 167.170 - Off Delaware Bay Approach Traffic Separation Scheme: General.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Separation Scheme: General. 167.170 Section 167.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.170 Off Delaware...

33 CFR 167.151 - Off New York: Precautionary areas.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.151 Off New York: Precautionary areas. (a) A.... (b) A precautionary area is established between the traffic separation scheme “Eastern Approach, off...

33 CFR 167.151 - Off New York: Precautionary areas.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.151 Off New York: Precautionary areas. (a) A.... (b) A precautionary area is established between the traffic separation scheme “Eastern Approach, off...

33 CFR 167.150 - Off New York Traffic Separation Scheme: General.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Scheme: General. 167.150 Section 167.150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.150 Off New York Traffic...

33 CFR 167.170 - Off Delaware Bay Approach Traffic Separation Scheme: General.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Separation Scheme: General. 167.170 Section 167.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.170 Off Delaware...

33 CFR 167.150 - Off New York Traffic Separation Scheme: General.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Scheme: General. 167.150 Section 167.150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.150 Off New York Traffic...

33 CFR 167.170 - Off Delaware Bay Approach Traffic Separation Scheme: General.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Separation Scheme: General. 167.170 Section 167.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.170 Off Delaware...

33 CFR 167.151 - Off New York: Precautionary areas.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.151 Off New York: Precautionary areas. (a) A.... (b) A precautionary area is established between the traffic separation scheme “Eastern Approach, off...

33 CFR 167.150 - Off New York Traffic Separation Scheme: General.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Scheme: General. 167.150 Section 167.150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.150 Off New York Traffic...

Geostatistical Interplay Between Geophysical and Geochemical Data: Mapping Litho-Structural Assemblages of Mesozoic Igneous Activities in the Parnaíba Basin (NE Brazil)

NASA Astrophysics Data System (ADS)

de Castro, David L.; Oliveira, Diógenes C.; Hollanda, Maria Helena B. M.

2018-07-01

Two widespread magmatic events are recorded in the Parnaíba basin (NE Brazil) during the Jurassic/Cretaceous opening of the Central and South Atlantic Oceans. The Early Jurassic ( 200 Ma) lava flows of the Mosquito Formation occur essentially in the western and southern basin segments, representing one of the largest expressions of the Central Atlantic Magmatic Province in the South American Plate. In contrast, sill complexes and dike swarms of the Early Cretaceous (129-124 Ma) Sardinha Formation occur in the eastern part of the basin and are chrono-correlated to the large Paraná-Etendeka igneous province and to the Rio Ceará-Mirim Dike Swarm. We gathered geophysical, well logging, outcrop analogs and geochemical data to recognize geometrical shapes and areal distribution patterns of igneous-related constructions. Seismic and well data reveal hundreds of km wide multilayered sill complexes and dikes, which are widespread across vast regions of the basin without evident structural control from either the Precambrian basement grain or the basin internal architecture. Anomaly enhancement techniques and self-organizing maps (SOM) procedure were applied on airborne magnetic data, unraveling near-surface magmatic features in four distinct magnetic domains. Using SOM analysis, the basaltic rocks were divided into six groups based on magnetic susceptibility and major elements composition. These results suggest common origin for both magmatic episodes, probably a combination of effects of edge-driven convection and large-scale mantle warming under the westward moving West Gondwana during the Central and South Atlantic opening, which caused a shifted emplacement to the east of the igneous rocks in the Parnaíba basin.

Geostatistical Interplay Between Geophysical and Geochemical Data: Mapping Litho-Structural Assemblages of Mesozoic Igneous Activities in the Parnaíba Basin (NE Brazil)

NASA Astrophysics Data System (ADS)

de Castro, David L.; Oliveira, Diógenes C.; Hollanda, Maria Helena B. M.

2018-02-01

Two widespread magmatic events are recorded in the Parnaíba basin (NE Brazil) during the Jurassic/Cretaceous opening of the Central and South Atlantic Oceans. The Early Jurassic ( 200 Ma) lava flows of the Mosquito Formation occur essentially in the western and southern basin segments, representing one of the largest expressions of the Central Atlantic Magmatic Province in the South American Plate. In contrast, sill complexes and dike swarms of the Early Cretaceous (129-124 Ma) Sardinha Formation occur in the eastern part of the basin and are chrono-correlated to the large Paraná-Etendeka igneous province and to the Rio Ceará-Mirim Dike Swarm. We gathered geophysical, well logging, outcrop analogs and geochemical data to recognize geometrical shapes and areal distribution patterns of igneous-related constructions. Seismic and well data reveal hundreds of km wide multilayered sill complexes and dikes, which are widespread across vast regions of the basin without evident structural control from either the Precambrian basement grain or the basin internal architecture. Anomaly enhancement techniques and self-organizing maps (SOM) procedure were applied on airborne magnetic data, unraveling near-surface magmatic features in four distinct magnetic domains. Using SOM analysis, the basaltic rocks were divided into six groups based on magnetic susceptibility and major elements composition. These results suggest common origin for both magmatic episodes, probably a combination of effects of edge-driven convection and large-scale mantle warming under the westward moving West Gondwana during the Central and South Atlantic opening, which caused a shifted emplacement to the east of the igneous rocks in the Parnaíba basin.

Kennedy Space Center and the Florida Atlantic coast area

NASA Image and Video Library

1974-02-01

SL4-93-167 (February 1974) --- A vertical view of the Kennedy Space Center and the Florida Atlantic coast area is seen in this Skylab 4 Earth Resources Experiments Package S190-B (five-inch earth terrain camera) infrared photography taken from the Skylab space station in Earth orbit. This photograph shows the major land-ocean features of the Florida coast near Vero Beach northward to Cape Canaveral and the KSC complex. The launch pads for the Skylab missions are clearly visible. Identification of living vegetation is possible through the use of the color infrared film. Various shades of red portray differences in the vegetation such as shown in the patterns in the agricultural area near Vero Beach. In the Kennedy Space Center, the nearly continuous and uniform red color shows that most of the land areas are heavily vegetated. The white coastal beach areas are strongly contrasted to the red land and the blue Atlantic Ocean. Old dunal areas in KSC are visible on Merritt Island which is separated from the Launch areas by the Banana River and the mainland by the Indian River. Federal and state highways and numerous causeways over the rivers are easily identified. The Florida mainland is partly shadowed by small white clouds which cast a pronounced shadow to the east of each cloud indicated the Sun is west of solar noon. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Core of Engineers. All EREP photography is available to the public through the Department of Interior's Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

Equilibrium Atmospheric Response to North Atlantic SST Anomalies.

NASA Astrophysics Data System (ADS)

Kushnir, Yochanan; Held, Isaac M.

1996-06-01

The equilibrium general circulation model (GCM) response to sea surface temperature (SST) anomalies in the western North Atlantic region is studied. A coarse resolution GCM, with realistic lower boundary conditions including topography and climatological SST distribution, is integrated in perpetual January and perpetual October modes, distinguished from one another by the strength of the midlatitude westerlies. An SST anomaly with a maximum of 4°C is added to the climatological SST distribution of the model with both positive and negative polarity. These anomaly runs are compared to one another, and to a control integration, to determine the atmospheric response. In all cases warming (cooling) of the midlatitude ocean surface yields a warming (cooling) of the atmosphere over and to the east of the SST anomaly center. The atmospheric temperature change is largest near the surface and decreases upward. Consistent with this simple thermal response, the geopotential height field displays a baroclinic response with a shallow anomalous low somewhat downstream from the warm SST anomaly. The equivalent barotropic, downstream response is weak and not robust. To help interpret the results, the realistic GCM integrations are compared with parallel idealized model runs. The idealized model has full physics and a similar horizontal and vertical resolution, but an all-ocean surface with a single, permanent zonal asymmetry. The idealized and realistic versions of the GCM display compatible response patterns that are qualitatively consistent with stationary, linear, quasigeostrophic theory. However, the idealized model response is stronger and more coherent. The differences between the two model response patterns can be reconciled based on the size of the anomaly, the model treatment of cloud-radiation interaction, and the static stability of the model atmosphere in the vicinity of the SST anomaly. Model results are contrasted with other GCM studies and observations.

Exploiting teleconnection indices for probabilistic forecasting of drought class transitions in Sicily region (Italy)

NASA Astrophysics Data System (ADS)

Bonaccorso, Brunella; Cancelliere, Antonino

2015-04-01

In the present study two probabilistic models for short-medium term drought forecasting able to include information provided by teleconnection indices are proposed and applied to Sicily region (Italy). Drought conditions are expressed in terms of the Standardized Precipitation-Evapotranspiration Index (SPEI) at different aggregation time scales. More specifically, a multivariate approach based on normal distribution is developed in order to estimate: 1) on the one hand transition probabilities to future SPEI drought classes and 2) on the other hand, SPEI forecasts at a generic time horizon M, as functions of past values of SPEI and the selected teleconnection index. To this end, SPEI series at 3, 4 and 6 aggregation time scales for Sicily region are extracted from the Global SPEI database, SPEIbase , available at Web repository of the Spanish National Research Council (http://sac.csic.es/spei/database.html), and averaged over the study area. In particular, SPEIbase v2.3 with spatial resolution of 0.5° lat/lon and temporal coverage between January 1901 and December 2013 is used. A preliminary correlation analysis is carried out to investigate the link between the drought index and different teleconnection patterns, namely: the North Atlantic Oscillation (NAO), the Scandinavian (SCA) and the East Atlantic-West Russia (EA-WR) patterns. Results of such analysis indicate a strongest influence of NAO on drought conditions in Sicily with respect to other teleconnection indices. Then, the proposed forecasting methodology is applied and the skill in forecasting of the proposed models is quantitatively assessed through the application of a simple score approach and of performance indices. Results indicate that inclusion of NAO index generally enhance model performance thus confirming the suitability of the models for short- medium term forecast of drought conditions.

Past and future warming of a deep European lake (Lake Lugano): What are the climatic drivers?

USGS Publications Warehouse

Lepori, Fabio; Roberts, James J.

2015-01-01

We used four decades (1972–2013) of temperature data from Lake Lugano, Switzerland and Italy, to address the hypotheses that: [i] the lake has been warming; [ii] part of the warming reflects global trends and is independent from climatic oscillations and [iii] the lake will continue to warm until the end of the 21st century. During the time spanned by our data, the surface waters of the lake (0–5 m) warmed at rates of 0.2–0.9 °C per decade, depending on season. The temperature of the deep waters (50-m bottom) displayed a rising trend in a meromictic basin of the lake and a sawtooth pattern in the other basin, which is holomictic. Long-term variation in surfacewater temperature correlated to global warming and multidecadal variation in two climatic oscillations, the Atlantic Multidecadal Oscillation (AMO) and the East Atlantic Pattern (EA).However, we did not detect an influence of the EA on the lake's temperature (as separate from the effect of global warming). Moreover, the effect of the AMO, estimated to a maximum of +1 °C, was not sufficient to explain the observed temperature increase (+2–3 °C in summer). Based on regional climate projections, we predicted that the lake will continue to warm at least until the end of the 21st century. Our results strongly suggest that the warming of Lake Lugano is tied to globalclimate change. To sustain current ecosystem conditions in Lake Lugano, we suggest that manage- ment plans that curtail eutrophication and (or) mitigation of global warming be pursued.

The Fronts and Atlantic Storm-Track Experiment (FASTEX): Scientific Objectives and Experimental Design.

NASA Astrophysics Data System (ADS)

Joly, Alain; Jorgensen, Dave; Shapiro, Melvyn A.; Thorpe, Alan; Bessemoulin, Pierre; Browning, Keith A.; Cammas, Jean-Pierre; Chalon, Jean-Pierre; Clough, Sidney A.; Emanuel, Kerry A.; Eymard, Laurence; Gall, Robert; Hildebrand, Peter H.; Langland, Rolf H.; Lemaître, Yvon; Lynch, Peter; Moore, James A.; Persson, P. Ola G.; Snyder, Chris; Wakimoto, Roger M.

1997-09-01

The Fronts and Atlantic Storm-Track Experiment (FASTEX) will address the life cycle of cyclones evolving over the North Atlantic Ocean in January and February 1997. The objectives of FASTEX are to improve the forecasts of end-of-storm-track cyclogenesis (primarily in the eastern Atlantic but with applicability to the Pacific) in the range 24 to 72 h, to enable the testing of theoretical ideas on cyclone formation and development, and to document the vertical and the mesoscale structure of cloud systems in mature cyclones and their relation to the dynamics. The observing system includes ships that will remain in the vicinity of the main baroclinic zone in the central Atlantic Ocean, jet aircraft that will fly and drop sondes off the east coast of North America or over the central Atlantic Ocean, turboprop aircraft that will survey mature cyclones off Ireland with dropsondes, and airborne Doppler radars, including ASTRAIA/ELDORA. Radiosounding frequency around the North Atlantic basin will be increased, as well as the number of drifting buoys. These facilities will be activated during multiple-day intensive observing periods in order to observe the same meteorological systems at several stages of their life cycle. A central archive will be developed in quasi-real time in Toulouse, France, thus allowing data to be made widely available to the scientific community.

Contrasting patterns of connectivity among endemic and widespread fire coral species ( Millepora spp.) in the tropical Southwestern Atlantic

NASA Astrophysics Data System (ADS)

de Souza, Júlia N.; Nunes, Flávia L. D.; Zilberberg, Carla; Sanchez, Juan A.; Migotto, Alvaro E.; Hoeksema, Bert W.; Serrano, Xaymara M.; Baker, Andrew C.; Lindner, Alberto

2017-09-01

Fire corals are the only branching corals in the South Atlantic and provide an important ecological role as habitat-builders in the region. With three endemic species ( Millepora brazilensis, M. nitida and M. laboreli) and one amphi-Atlantic species ( M. alcicornis), fire coral diversity in the Brazilian Province rivals that of the Caribbean Province. Phylogenetic relationships and patterns of population genetic structure and diversity were investigated in all four fire coral species occurring in the Brazilian Province to understand patterns of speciation and biogeography in the genus. A total of 273 colonies from the four species were collected from 17 locations spanning their geographic ranges. Sequences from the 16S ribosomal DNA (rDNA) were used to evaluate phylogenetic relationships. Patterns in genetic diversity and connectivity were inferred by measures of molecular diversity, analyses of molecular variance, pairwise differentiation, and by spatial analyses of molecular variance. Morphometrics of the endemic species M. braziliensis and M. nitida were evaluated by discriminant function analysis; macro-morphological characters were not sufficient to distinguish the two species. Genetic analyses showed that, although they are closely related, each species forms a well-supported clade. Furthermore, the endemic species characterized a distinct biogeographic barrier: M. braziliensis is restricted to the north of the São Francisco River, whereas M. nitida occurs only to the south. Millepora laboreli is restricted to a single location and has low genetic diversity. In contrast, the amphi-Atlantic species M. alcicornis shows high genetic connectivity within the Brazilian Province, and within the Caribbean Province (including Bermuda), despite low levels of gene flow between these populations and across the tropical Atlantic. These patterns reflect the importance of the Amazon-Orinoco Plume and the Mid-Atlantic Barrier as biogeographic barriers, and suggest that, while M. alcicornis is capable of long-distance dispersal, the three endemics have restricted ranges and more limited dispersal capabilities.

Arctic climatechange and its impacts on the ecology of the North Atlantic.

PubMed

Greene, Charles H; Pershing, Andrew J; Cronin, Thomas M; Ceci, Nicole

2008-11-01

Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends in sea ice, freshwater export, and surface ocean salinity continue. It is more difficult to predict ecological responses to abrupt climate change in the more distant future as tipping points in the Earth's climate system are exceeded.

Northern tropical Atlantic climate since late Medieval times from Northern Caribbean coral geochemistry

NASA Astrophysics Data System (ADS)

Kilbourne, K. H.; Xu, Y.

2015-12-01

Paleoclimate reconstructions of different global climate modes over the last 1000 years provide the basis for testing the relative roles of forced and unforced variability climate system, which can help us improve projections of future climate change. The Medieval Climate Anomaly (MCA) has been characterized by a combination of persistent La Niña-like conditions, a positive North Atlantic Oscillation (+NAO), and increased Atlantic Meridional Overturning Circulation (AMOC). The northern tropical Atlantic is sensitive to each of these climate patterns, but not all of them have the same regional fingerprint in the modern northern tropical Atlantic. The relative influence of different processes related to these climate patterns can help us better understand regional responses to climate change. The regional response of the northern tropical Atlantic is important because the tropical Atlantic Ocean is a large source of heat and moisture to the global climate system that can feedback onto global climate patterns. This study presents new coral Sr/Ca and δ18O data from the northern tropical Atlantic (Anegada, British Virgin Islands). Comparison of the sub-fossil corals that grew during the 13th and 14th Centuries with modern coral geochemical data from this site indicates relatively cooler mean conditions with a decrease in the oxygen isotopic composition of the water consistent with lower salinities. Similar average annual cycles between modern and sub-fossil Sr/Ca indicate no change in seasonal temperature range, but a difference in the relative phasing of the δ18O seasonal cycles indicates that the fresher mean conditions may be due to a more northerly position of the regional salinity front. This localized response is consistent with some, but not all of the expected regional responses to a La Niña-like state, a +NAO state, and increased AMOC. Understanding these differences can provide insight into the relative importance of advection versus surface fluxes for heat and salt balances at the study site. Ultimately the data support the existing framework for understanding climate during the MCA and demonstrate the importance of regional processes in understanding historic and future climate patterns.

Long-Term Simulation of Dust Distribution with the GOCART Model: Correlation with the North Atlantic Oscillation

NASA Technical Reports Server (NTRS)

Ginoux, P.; Prospero, J.; Torres, O.; Chin, M.

2002-01-01

Global distribution of aeolian dust is simulated from 1981 to 1996 with the Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. The results are assessed with in-situ measurements and the Total Ozone Mapping Spectrometer (TOMS) aerosol products. The annual budget over the different continents and oceans are analyzed. It is found that there is a maximum of 25% difference of global annual emission from the minimum in 1996 to the maximum in 1988. There is a downward trend of dust emission over Africa and East Asia, of 6 and 2 Tg/yr, respectively. The inter-annual variability of dust distribution is analyzed over the North Atlantic and Africa. It is found that in winter most of the North Atlantic and Africa dust loading is correlated with the North Atlantic Oscillation. The GOCART model indicates that a controlling factor of such correlation can be attributed to dust emission from the Sahel. The Bodele depression is the major dust source in winter and its inter-annual variability is highly correlated with the NAO. However, it is not possible to conclude without further analysis that the North Atlantic Oscillation is forcing the inter-annual variability of dust emission and in-turn dust concentration over the North Atlantic.

Late Pleistocene glacial fluctuations in Cordillera Oriental, subtropical Andes

NASA Astrophysics Data System (ADS)

Martini, Mateo A.; Kaplan, Michael R.; Strelin, Jorge A.; Astini, Ricardo A.; Schaefer, Joerg M.; Caffee, Marc W.; Schwartz, Roseanne

2017-09-01

The behavior of subtropical glaciers during Middle to Late Pleistocene global glacial maxima and abrupt climate change events, specifically in Earth's most arid low-latitude regions, remains an outstanding problem in paleoclimatology. The present-day climate of Cordillera Oriental, in arid northwestern Argentina, is influenced by shifts in subtropical climate systems, including the South American Summer Monsoon. To understand better past glacier-subtropical climates during the global Last Glacial Maximum (LGM, 26.5-19 ka) and other time periods, we combined geomorphic features with forty-two precise 10Be ages on moraine boulders and reconstructed paleo-equilibrium line altitudes (ELA) at Nevado de Chañi (24°S) in the arid subtropical Andes. We found a major glacial expansion at ∼23 ± 1.6 ka, that is, during the global LGM. Additional glacial expansions are observed before the global LGM (at ∼52-39 ka), and after, at 15 ± 0.5 and 12 ± 0.6 ka. The ∼15 ka glacial event was found on both sides of Chañi and the ∼12 ka event is only recorded on the east side. Reconstructed ELAs of the former glaciers exhibit a rise from east to west that resembles the present subtropical climate trajectory from the Atlantic side of the continent; hence, we infer that this climate pattern must have been present in the past. Based on comparison with other low-latitude paleoclimate records, such as those from lakes and caves, we infer that both temperature and precipitation influenced past glacial occurrence in this sector of the arid Andes. Our findings also imply that abrupt deglacial climate events associated with the North Atlantic, specifically curtailed meridional overturning circulation and regional cooling, may have had attendant impacts on low subtropical Southern Hemisphere latitudes, including the climate systems that affect glacial activity around Nevado de Chañi.

Changes in Nematode Communities in Different Physiographic Sites of the Condor Seamount (North-East Atlantic Ocean) and Adjacent Sediments

PubMed Central

Zeppilli, Daniela; Bongiorni, Lucia; Serrão Santos, Ricardo; Vanreusel, Ann

2014-01-01

Several seamounts are known as ‘oases’ of high abundances and biomass and hotspots of biodiversity in contrast to the surrounding deep-sea environments. Recent studies have indicated that each single seamount can exhibit a high intricate habitat turnover. Information on alpha and beta diversity of single seamount is needed in order to fully understand seamounts contribution to regional and global biodiversity. However, while most of the seamount research has been focused on summits, studies considering the whole seamount structure are still rather poor. In the present study we analysed abundance, biomass and diversity of nematodes collected in distinct physiographic sites and surrounding sediments of the Condor Seamount (Azores, North-East Atlantic Ocean). Our study revealed higher nematode biomass in the seamount bases and values 10 times higher in the Condor sediments than in the far-field site. Although biodiversity indices did not showed significant differences comparing seamount sites and far-field sites, significant differences were observed in term of nematode composition. The Condor summit harboured a completely different nematode community when compared to the other seamount sites, with a high number of exclusive species and important differences in term of nematode trophic diversity. The oceanographic conditions observed around the Condor Seamount and the associated sediment mixing, together with the high quality of food resources available in seamount base could explain the observed patterns. Our results support the hypothesis that seamounts maintain high biodiversity through heightened beta diversity and showed that not only summits but also seamount bases can support rich benthic community in terms of standing stocks and diversity. Furthermore functional diversity of nematodes strongly depends on environmental conditions link to the local setting and seamount structure. This finding should be considered in future studies on seamounts, especially in view of the potential impacts due to current and future anthropogenic threats. PMID:25541988

Teleconnection between sea ice in the Barents Sea in June and the Silk Road, Pacific-Japan and East Asian rainfall patterns in August

NASA Astrophysics Data System (ADS)

He, Shengping; Gao, Yongqi; Furevik, Tore; Wang, Huijun; Li, Fei

2018-01-01

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes. Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east-west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific-Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.

Teleconnection between Sea Ice in the Barents Sea in June and the Silk Road, Pacific-Japan and East Asian Rainfall Patterns in August

NASA Astrophysics Data System (ADS)

He, S.; Gao, Y.; Furevik, T.; Huijun, W.; Li, F.

2017-12-01

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes. Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east-west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific-Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.

Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States

USGS Publications Warehouse

McCabe, G.J.; Palecki, M.A.; Betancourt, J.L.

2004-01-01

More than half (52%) of the spatial and temporal variance in multidecadal drought frequency over the conterminous United States is attributable to the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). An additional 22% of the variance in drought frequency is related to a complex spatial pattern of positive and negative trends in drought occurrence possibly related to increasing Northern Hemisphere temperatures or some other unidirectional climate trend. Recent droughts with broad impacts over the conterminous U.S. (1996, 1999-2002) were associated with North Atlantic warming (positive AMO) and north-eastern and tropical Pacific cooling (negative PDO). Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought.

Author Correction: North Atlantic variability and its links to European climate over the last 3000 years.

PubMed

Moffa-Sánchez, Paola; Hall, Ian R

2018-02-15

In the original version of this Article, the third sentence of the first paragraph of the "Changes in the input of polar waters into the Labrador Sea" section of the Results originally incorrectly read 'During the spring-summer months, after the winter convection has ceased in the Labrador Sea, its northwest boundary currents (the EGC and IC) support restratification of the surface ocean through lateral transport.' The correct version states 'northeast' instead of 'northwest'. The fifth sentence of the second paragraph of the same section originally incorrectly read "In contrast, in the western section of the Nordic Seas, under the presence of warm Atlantic waters of the Norwegian Current, Nps was found to calcify deeper in the water column (100-200 m), whereas in the east under the influence of the EGC polar waters it calcified closer to the surface at a similar depth as Tq 23 ." The correct version states 'eastern' instead of 'western' and 'west' instead of 'east'.The seventh sentence of the same paragraph originally incorrectly read "Small/large differences in Δδ 18 O Nps-Tq indicating increased/decreased presence of warm and salty Atlantic IC waters vs. polar EGC waters in the upper water column, respectively." The correct version starts 'Large/small' rather than 'Small/large'.These errors have been corrected in both the PDF and HTML versions of the Article.

Sedimentation in the Kane fracture zone, western North Atlantic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaroslow, G.E.

1991-03-01

The Kane fracture zone, a deep narrow trough in oceanic crust, has provided an ideal depocenter for reservation on the seismic stratigraphic record of the North Atlantic basin. The acoustic stratigraphy in single-channel and multichannel seismic reflection profiles crossing the Kane fracture zone in the western North Atlantic has been examined in order to scrutinize age processes within a fracture zone. Maps of total sediment thickness have provided insight into overall sediment distribution and the influence of topography on sedimentation. Eight reflectors have been traced and correlated with lithostratigraphy at Deep Sea Drilling Project (DSDP) sites. The Bermuda Rise, amore » prominent topographic feature, has had a profound effect on the distribution of sediments within the fracture zone. Since late Eocene, the rise has blocked transport by turbidity currents of terrigenous sediments to distal portions of the fracture valley. A 1,000-m-thick turbidite pond within the fracture zone east of the Bermuda Rise has been determined to have been derived from local sources. Within the ponded sequence a seismic discontinuity is estimated to be early Oligocene and postdates the emergence of the Bermuda Rise, adding an independent age constraint on the development of the rise. The pond terminates against a structural dam at 55{degree}20W, east of which the fracture zone is essentially sediment starved.« less

33 CFR 80.165 - New York Harbor.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false New York Harbor. 80.165 Section 80.165 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.165 New York Harbor. A line drawn from East...

North American Biome

USDA-ARS?s Scientific Manuscript database

The North America biome includes the major ecoregions that make up the land area of Canada, the United States, Mexico, and countries in Central America. The biome is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the s...

Atlas of NATO.

ERIC Educational Resources Information Center

Young, Harry F.

This atlas provides basic information about the North Atlantic Treaty Organization (NATO). Formed in response to growing concern for the security of Western Europe after World War II, NATO is a vehicle for Western efforts to reduce East-West tensions and the level of armaments. NATO promotes political and economic collaboration as well as military…

National Waterways Study. Review of National Defense Emergency and Safety Issues Affecting the Waterways.

DTIC Science & Technology

1981-07-01

Sheffield, AL Arkansas River Fort Chaffee Fort Smith , AR Pine Bluff Arsenal Pine Bluff, AR Gulf Coast East Fort Benning Columbus, GA Middle Atlantic...Pittsburgh District, United States Army Corps of Engineers. Pittsburgh, Pennsylvania: United States Army Corps of Engineers [no date]. MacLeay, Lachlan

Passive Sampling in Regulatory Chemical Monitoring of Nonpolar Organic Compounds in the Aquatic Environment

EPA Science Inventory

We reviewed compliance monitoring requirements in the European Union (EU), the United States(USA), and the Oslo-Paris Convention for the protection of the marine environment of the North-East Atlantic (OSPAR), and evaluated if these are met by passive sampling methods for nonpola...

33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Bay Traffic Separation Scheme: General. 167.200 Section 167.200 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic...

33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Bay Traffic Separation Scheme: General. 167.200 Section 167.200 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic...

33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Bay Traffic Separation Scheme: General. 167.200 Section 167.200 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic...

33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Bay Traffic Separation Scheme: General. 167.200 Section 167.200 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic...

33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Bay Traffic Separation Scheme: General. 167.200 Section 167.200 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic...

50 CFR 622.491 - Seasonal and area closures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.491 Seasonal and area... which includes Lang Bank east of St. Croix, U.S. Virgin Islands. (b) Pursuant to the procedures and...

Exploring the effects of climatic variables on monthly precipitation variation using a continuous wavelet-based multiscale entropy approach.

PubMed

Roushangar, Kiyoumars; Alizadeh, Farhad; Adamowski, Jan

2018-08-01

Understanding precipitation on a regional basis is an important component of water resources planning and management. The present study outlines a methodology based on continuous wavelet transform (CWT) and multiscale entropy (CWME), combined with self-organizing map (SOM) and k-means clustering techniques, to measure and analyze the complexity of precipitation. Historical monthly precipitation data from 1960 to 2010 at 31 rain gauges across Iran were preprocessed by CWT. The multi-resolution CWT approach segregated the major features of the original precipitation series by unfolding the structure of the time series which was often ambiguous. The entropy concept was then applied to components obtained from CWT to measure dispersion, uncertainty, disorder, and diversification of subcomponents. Based on different validity indices, k-means clustering captured homogenous areas more accurately, and additional analysis was performed based on the outcome of this approach. The 31 rain gauges in this study were clustered into 6 groups, each one having a unique CWME pattern across different time scales. The results of clustering showed that hydrologic similarity (multiscale variation of precipitation) was not based on geographic contiguity. According to the pattern of entropy across the scales, each cluster was assigned an entropy signature that provided an estimation of the entropy pattern of precipitation data in each cluster. Based on the pattern of mean CWME for each cluster, a characteristic signature was assigned, which provided an estimation of the CWME of a cluster across scales of 1-2, 3-8, and 9-13 months relative to other stations. The validity of the homogeneous clusters demonstrated the usefulness of the proposed approach to regionalize precipitation. Further analysis based on wavelet coherence (WTC) was performed by selecting central rain gauges in each cluster and analyzing against temperature, wind, Multivariate ENSO index (MEI), and East Atlantic (EA) and North Atlantic Oscillation (NAO), indeces. The results revealed that all climatic features except NAO influenced precipitation in Iran during the 1960-2010 period. Copyright © 2018 Elsevier Inc. All rights reserved.

A genomewide catalogue of single nucleotide polymorphisms in white-beaked and Atlantic white-sided dolphins.

PubMed

Fernández, R; Schubert, M; Vargas-Velázquez, A M; Brownlow, A; Víkingsson, G A; Siebert, U; Jensen, L F; Øien, N; Wall, D; Rogan, E; Mikkelsen, B; Dabin, W; Alfarhan, A H; Alquraishi, S A; Al-Rasheid, K A S; Guillot, G; Orlando, L

2016-01-01

The field of population genetics is rapidly moving into population genomics as the quantity of data generated by high-throughput sequencing platforms increases. In this study, we used restriction-site-associated DNA sequencing (RADSeq) to recover genomewide genotypes from 70 white-beaked (Lagenorhynchus albirostris) and 43 Atlantic white-sided dolphins (L. acutus) gathered throughout their north-east Atlantic distribution range. Both species are at a high risk of being negatively affected by climate change. Here, we provide a resource of 38,240 RAD-tags and 52,981 nuclear SNPs shared between both species. We have estimated overall higher levels of nucleotide diversity in white-sided (π = 0.0492 ± 0.0006%) than in white-beaked dolphins (π = 0.0300 ± 0.0004%). White-sided dolphins sampled in the Faroe Islands, belonging to two pods (N = 7 and N = 11), showed similar levels of diversity (π = 0.0317 ± 0.0007% and 0.0267 ± 0.0006%, respectively) compared to unrelated individuals of the same species sampled elsewhere (e.g. π = 0.0285 ± 0.0007% for 11 Scottish individuals). No evidence of higher levels of kinship within pods can be derived from our analyses. When identifying the most likely number of genetic clusters among our sample set, we obtained an estimate of two to four clusters, corresponding to both species and possibly, two further clusters within each species. A higher diversity and lower population structuring was encountered in white-sided dolphins from the north-east Atlantic, in line with their preference for pelagic waters, as opposed to white-beaked dolphins that have a more patchy distribution, mainly across continental shelves. © 2015 John Wiley & Sons Ltd.

Atlantic Induced Pan-tropical Climate Variability in the Upper-ocean and Atmosphere

NASA Astrophysics Data System (ADS)

Li, X.; Xie, S. P.; Gille, S. T.; Yoo, C.

2016-02-01

During the last three decades, tropical sea surface temperature (SST) exhibited dipole-like trends, with warming over the tropical Atlantic and Indo-Western Pacific but cooling over the Eastern Pacific. The Eastern Pacific cooling has recently been identified as a driver of the global warming hiatus. Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian Ocean, which could potentially contribute to this zonally asymmetric SST pattern. However, the mechanisms and the interactions between these teleconnections remain unclear. To investigate these questions, we performed a `pacemaker' simulation by restoring the tropical Atlantic SST changes in a state-of-the-art climate model - the CESM1. Results show that the Atlantic plays a key role in initiating the tropical-wide teleconnections, and the Atlantic-induced anomalies contribute 55%-75% of the total tropical SST and circulation changes during the satellite era. A hierarchy of oceanic and atmospheric models are then used to investigate the physical mechanisms of these teleconnections: the Atlantic warming enhances atmospheric deep convection, drives easterly wind anomalies over the Indo-Western Pacific through the Kelvin wave, and westerly anomalies over the eastern Pacific as Rossby waves, in line with Gill's solution (Fig1a). These wind changes induce an Indo-Western Pacific warming via the wind-evaporation-SST effect, and this warming intensifies the La Niña-type response in the upper Pacific Ocean by enhancing the easterly trade winds and through the Bjerknes ocean-dynamical processes (Fig1b). The teleconnection finally develops into a tropical-wide SST dipole pattern with an enhanced trade wind and Walker circulation, similar as the observed changes during the satellite era. This mechanism reveals that the tropical ocean basins are more tightly connected than previously thought, and the Atlantic plays a key role in the tropical climate pattern formation and further the global warming hiatus. The tropical Atlantic warming is likely due to radiative forcing and Atlantic meridional overturning circulation (AMOC). Our study suggests that the AMOC may force the decadal variability of the tropical ocean and atmosphere, and thus contributes to the decadal predictability of the global climate.

The impact of boreal autumn SST anomalies over the South Pacific on boreal winter precipitation over East Asia

NASA Astrophysics Data System (ADS)

Ao, Juan; Sun, Jianqi

2016-05-01

The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies (SSTAs) over the South Pacific Ocean (SPO) in boreal autumn are closely related to the variability in the dipole pattern of boreal winter precipitation over East Asia. The physical link between the boreal autumn SPO SSTAs and the boreal winter East Asian precipitation dipole pattern is shown to mainly be the seasonal persistence of the SPO SSTAs themselves. The seasonal persistence of the SPO SSTAs can memorize and transport the signal of the boreal autumn SSTAs to the following winter, and then stimulates a meridional teleconnection pattern from the SH to the NH, resulting in a meridional dipole pattern of atmospheric circulation over East Asia in boreal winter. As a major influencing factor, this dipole pattern of the atmospheric circulation can finally lead to the anomalous precipitation dipole pattern over East Asia in boreal winter. These observed physical processes are further confirmed in this study through numerical simulation. The evidence from this study, showing the impact of the SPO SSTAs in boreal autumn, not only deepens our understanding of the variability in East Asian boreal winter precipitation, but also provides a potentially useful predictor for precipitation in the region.

Remote Drying in the North Atlantic as a Common Response to Precessional Changes and CO 2 Increase Over Land

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Patrick; Kravitz, Ben; Lu, Jian

In this study, we demonstrate that changes of the North Atlantic subtropical high and its regional rainfall pattern during mid-Holocene precessional changes and idealized 4xCO 2 increase can both be understood as a remote response to increased land heating near North Africa. Despite different sources and patterns of radiative forcing (increase in CO 2 concentration versus changes in orbital parameters), we find that the pattern of energy, circulation, and rainfall responses in the Northern Hemisphere summer subtropics are remarkably similar in the two forcing scenarios because both are dominated by the same land-sea heating contrast in response to the forcing.more » An increase in energy input over arid land drives a westward displacement of the coupled North Atlantic subtropical high-monsoon circulation, consistent with increased precipitation in the Afro-Asia region and decreased precipitation in the America-Atlantic region. This study underscores the importance of land heating in dictating remote drying through zonal shifts of the subtropical circulation.« less

Remote Drying in the North Atlantic as a Common Response to Precessional Changes and CO 2 Increase Over Land

DOE PAGES

Kelly, Patrick; Kravitz, Ben; Lu, Jian; ...

2018-04-16

In this study, we demonstrate that changes of the North Atlantic subtropical high and its regional rainfall pattern during mid-Holocene precessional changes and idealized 4xCO 2 increase can both be understood as a remote response to increased land heating near North Africa. Despite different sources and patterns of radiative forcing (increase in CO 2 concentration versus changes in orbital parameters), we find that the pattern of energy, circulation, and rainfall responses in the Northern Hemisphere summer subtropics are remarkably similar in the two forcing scenarios because both are dominated by the same land-sea heating contrast in response to the forcing.more » An increase in energy input over arid land drives a westward displacement of the coupled North Atlantic subtropical high-monsoon circulation, consistent with increased precipitation in the Afro-Asia region and decreased precipitation in the America-Atlantic region. This study underscores the importance of land heating in dictating remote drying through zonal shifts of the subtropical circulation.« less

Dry or wet in East Asia during North Atlantic cooling? New perspectives from multiproxy climate records and coupled model simulations

NASA Astrophysics Data System (ADS)

Zhang, H.; Griffiths, M. L.; Wu, S.; Kong, W.; Chiang, J. C. H.; Atwood, A. R.; Cheng, H.; Huang, J.; Xie, S.

2017-12-01

Chinese speleothem δ18Oc records have revealed that the Asian summer monsoon underwent pronounced millennial-scale variability during the last deglaciation, yet there is still debate as to what the δ18Oc signals represent. Traditionally, these δ18Oc records were interpreted as a proxy for regional rainfall variability via the East Asian Summer Monsoon (EASM), however, recent isotope-enabled model simulations have suggested that precipitation δ18O over central China is more a reflection of rainfall in the upstream region of the Indian monsoon. Therefore, despite the increased number of speleothem records emerging from the EASM region, we still lack a robust understanding of how local monsoon rainfall variability fluctuated in central China during the last deglaciation. To address this, here we present two new multiproxy speleothem records from Haozhu Cave (HZ), central China, during the deglaciation. HZ δ18Oc time series largely parallel those from other distal cave sites in China and India, suggesting that the oxygen isotopes are indeed dominated by upstream rainout. To inspect the local hydrology, we also examined Sr-Mg-Ba/Ca ratios and d13C. Interestingly, results show that during Heinrich Stadial 1 and the Younger Dryas, the d13C and trace elements decrease significantly, which we interpret to reflect higher cave recharge. Thus, despite a weakened Indian monsoon during these cooling events (inferred from the δ18Oc), our results suggest that central China was in fact wetter. To test this hypothesis, we examined past rainfall variability in China using CESM1.0.5 imposed with 1Sv of North Atlantic (NA) fresh water forcing. Similar to the proxies, results from these simulations demonstrate that south-central China was wetter following NA cooling, whilst northern China was drier. This `dipole' pattern can best be explained by a seasonally-lagged onset of the mei-yu stage of monsoon evolution. A later onset of mei-yu to midsummer during NA cooling would have resulted in a shorter midsummer stage, leaving south-central China wet at the expense of dry conditions to the north. Our proxy and model results thus support a recent hypothesis, that paleoclimate changes over East Asia reflect the timing and duration of its intraseasonal stages, modulated by the position of the westerlies relative to the Tibetan Plateau.

Temporal and directional patterns of nymphal Halyomorpha halys (Hemiptera: Pentatomidae) movement on the trunk of selected wild and fruit tree hosts in the Mid-Atlantic Region

USDA-ARS?s Scientific Manuscript database

Halyomorpha halys (Stal) (Hemiptera: Pentatomidae) is an invasive and polyphagous herbivore that has been problematic in Mid-Atlantic fruit orchards, many of which are adjacent to woodlands containing its wild hosts. Our tree census in woodlands bordering 15 Mid-Atlantic apple orchards revealed 47 ...

The oldest Mahonia (Berberidaceae) fossil from East Asia and its biogeographic implications.

PubMed

Huang, Jian; Su, Tao; Lebereton-Anberrée, Julie; Zhang, Shi-Tao; Zhou, Zhe-Kun

2016-03-01

Interpretation of the biogeography of the genus Mahonia (Berberidaceae) is limited by the lack of fossil records in East Asia. Compressed fossil foliage, described here as Mahonia mioasiatica sp. nov., were collected from the Upper Miocene Xiaolongtan Formation in Wenshan, Yunnan, southwest China. These specimens represent the oldest reliable fossil record of Mahonia in East Asia. This new fossil species shows a general similarity to Group Orientales and is most similar to the extant eastern Asian Mahonia conferta. Considering other fossil evidence of Mahonia, we propose a migration route of this genus to Asia over the North Atlantic Land Bridge rather than the Bering Land Bridge. Our results also suggest that North America, Europe and East Asia have been successive centers of diversity for the genus, as a consequence of diversification in Group Orientales potentially related to historical climate change.

Correlation and anti-correlation of the East Asian summer and winter monsoons during the last 21,000 years.

PubMed

Wen, Xinyu; Liu, Zhengyu; Wang, Shaowu; Cheng, Jun; Zhu, Jiang

2016-06-22

Understanding the past significant changes of the East Asia Summer Monsoon (EASM) and Winter Monsoon (EAWM) is critical for improving the projections of future climate over East Asia. One key issue that has remained outstanding from the paleo-climatic records is whether the evolution of the EASM and EAWM are correlated. Here, using a set of long-term transient simulations of the climate evolution of the last 21,000 years, we show that the EASM and EAWM are positively correlated on the orbital timescale in response to the precessional forcing, but are anti-correlated on millennial timescales in response to North Atlantic melt water forcing. The relation between EASM and EAWM can differ dramatically for different timescales because of the different response mechanisms, highlighting the complex dynamics of the East Asian monsoon system and the challenges for future projection.

Correlation and anti-correlation of the East Asian summer and winter monsoons during the last 21,000 years

PubMed Central

Wen, Xinyu; Liu, Zhengyu; Wang, Shaowu; Cheng, Jun; Zhu, Jiang

2016-01-01

Understanding the past significant changes of the East Asia Summer Monsoon (EASM) and Winter Monsoon (EAWM) is critical for improving the projections of future climate over East Asia. One key issue that has remained outstanding from the paleo-climatic records is whether the evolution of the EASM and EAWM are correlated. Here, using a set of long-term transient simulations of the climate evolution of the last 21,000 years, we show that the EASM and EAWM are positively correlated on the orbital timescale in response to the precessional forcing, but are anti-correlated on millennial timescales in response to North Atlantic melt water forcing. The relation between EASM and EAWM can differ dramatically for different timescales because of the different response mechanisms, highlighting the complex dynamics of the East Asian monsoon system and the challenges for future projection. PMID:27328616

The role of local sea surface temperature pattern changes in shaping climate change in the North Atlantic sector

NASA Astrophysics Data System (ADS)

Hand, Ralf; Keenlyside, Noel S.; Omrani, Nour-Eddine; Bader, Jürgen; Greatbatch, Richard J.

2018-03-01

Beside its global effects, climate change is manifested in many regionally pronounced features mainly resulting from changes in the oceanic and atmospheric circulation. Here we investigate the influence of the North Atlantic SST on shaping the winter-time response to global warming. Our results are based on a long-term climate projection with the Max Planck Institute Earth System Model (MPI-ESM) to investigate the influence of North Atlantic sea surface temperature pattern changes on shaping the atmospheric climate change signal. In sensitivity experiments with the model's atmospheric component we decompose the response into components controlled by the local SST structure and components controlled by global/remote changes. MPI-ESM simulates a global warming response in SST similar to other climate models: there is a warming minimum—or "warming hole"—in the subpolar North Atlantic, and the sharp SST gradients associated with the Gulf Stream and the North Atlantic Current shift northward by a few a degrees. Over the warming hole, global warming causes a relatively weak increase in rainfall. Beyond this, our experiments show more localized effects, likely resulting from future SST gradient changes in the North Atlantic. This includes a significant precipitation decrease to the south of the Gulf Stream despite increased underlying SSTs. Since this region is characterised by a strong band of precipitation in the current climate, this is contrary to the usual case that wet regions become wetter and dry regions become drier in a warmer climate. A moisture budget analysis identifies a complex interplay of various processes in the region of modified SST gradients: reduced surface winds cause a decrease in evaporation; and thermodynamic, modified atmospheric eddy transports, and coastal processes cause a change in the moisture convergence. The changes in the the North Atlantic storm track are mainly controlled by the non-regional changes in the forcing. The impact of the local SST pattern changes on regions outside the North Atlantic is small in our setup.

The North Atlantic Oscillation and the ITCZ in a climate simulation

NASA Astrophysics Data System (ADS)

Cavalcanti, I. F. A.; Souza, P.

2009-04-01

The North Atlantic Oscillation (NAO) and the Atlantic Intertropical Convergence Zone (ITCZ) features are analyzed in a climate simulation with the CPTEC/COLA AGCM. The CPTEC/COLA AGCM reproduces the ITCZ seasonal north-south displacement as well as the seasonal east-west intensity, but the model overestimates the convection. The two phases of NAO are well simulated in the four seasons and also the largest intensity in DJF. The main mode of atmospheric variability considering the North and South Atlantic region, which displays a shifting of the NAO centers and a center of action over South Atlantic to the south of Africa is also reproduced. This mode, in DJF, is associated with the north-south ITCZ displacement in April, in the observed data. The displacement of the NAO centers southwestward allows the increase of pressure over the tropical North Atlantic Ocean and the increase of trade winds and displacement of the confluence and convergence zone southwards. The opposite occurs when the centers are displaced northeastward. The model Atlantic ITCZ position in April is associated with the anomalous (observed) Atlantic SST and the southward displacement of the confluence zone, but the simulated atmospheric features in DJF does not display the main mode of variability, as in the observations. This occurs due to the lack of interaction between the atmosphere and ocean in the atmospheric model. While in the observations the physical mechanism that links the NAO centers of action to the ITCZ position is the ocean-atmosphere interaction, from DJF to April, the atmospheric model responds to the prescribed SST at the same month, in April.

Ocean impact on decadal Atlantic climate variability revealed by sea-level observations.

PubMed

McCarthy, Gerard D; Haigh, Ivan D; Hirschi, Joël J-M; Grist, Jeremy P; Smeed, David A

2015-05-28

Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall, European summer precipitation, Atlantic hurricanes and variations in global temperatures. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres--the intergyre region. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States.

A tripolar pattern as an internal mode of the East Asian summer monsoon

NASA Astrophysics Data System (ADS)

Hirota, Nagio; Takahashi, Masaaki

2012-11-01

A tripolar anomaly pattern with centers located around the Philippines, China/Japan, and East Siberia dominantly appears in climate variations of the East Asian summer monsoon. In this study, we extracted this pattern as the first mode of a singular value decomposition (SVD1) over East Asia. The squared covariance fraction of SVD1 was 59 %, indicating that this pattern can be considered a dominant pattern of climate variations. Moreover, the results of numerical experiments suggested that the structure is also a dominant pattern of linear responses, even if external forcing is distributed homogeneously over the Northern Hemisphere. Thus, the tripolar pattern can be considered an internal mode that is characterized by the internal atmospheric processes. In this pattern, the moist processes strengthen the circulation anomalies, the dynamical energy conversion supplies energy to the anomalies, and the Rossby waves propagate northward in the lower troposphere and southeastward in the upper troposphere. These processes are favorable for the pattern to have large amplitude and to influence a large area.

The impact of North Atlantic wind and cyclone trends on European precipitation and significant wave height in the Atlantic.

PubMed

Trigo, Ricardo M; Valente, Maria A; Trigo, Isabel F; Miranda, Pedro M A; Ramos, Alexandre M; Paredes, Daniel; García-Herrera, Ricardo

2008-12-01

An analysis of the frequency of cyclones and surface wind velocity for the Euro-Atlantic sector is performed by means of an objective methodology. Monthly and seasonal trends of cyclones and wind speed magnitude are computed and trends between 1960 and 2000 evaluated. Results reveal a significant frequency decrease (increase) in the western Mediterranean (Greenland and Scandinavia), particularly in December, February, and March. Seasonal and monthly analysis of wind magnitude trends shows similar spatial patterns. We show that these changes in the frequency of low-pressure centers and the associated wind patterns are partially responsible for trends in the significant height of waves. Throughout the extended winter months (October-March), regions with positive (negative) wind magnitude trends, of up to 5 cm/s/year, often correspond to regions of positive (negative) significant wave height trends. The cyclone and wind speed trends computed for January-March are well matched by the corresponding trends in significant wave height, with February being the month with the highest trends (negative south of lat 50 degrees N up to -3 cm/year, and positive up to 5 cm/year just north of Scotland). Trends in European precipitation are assessed using the Climatic Research Unit data set. The results of the assessment emphasize the link with the corresponding tendencies of cyclone frequencies. Finally, it is shown that these changes are associated, to a large extent, with the preferred phases of major large-scale atmospheric circulation modes, particularly with the North Atlantic Oscillation, the eastern Atlantic pattern, and the Scandinavian pattern.

Solar wind: A possible factor driving the interannual sea surface temperature tripolar mode over North Atlantic

NASA Astrophysics Data System (ADS)

Xiao, Ziniu; Li, Delin

2016-06-01

The effect of solar wind (SW) on the North Atlantic sea surface temperature (SST) in boreal winter is examined through an analysis of observational data during 1964-2013. The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed (SWS) variations. This pattern is broadly similar to the leading empirical orthogonal function (EOF) mode of interannual variations in the wintertime SSTs over North Atlantic. The time series of this leading EOF mode of SST shows a significant interannual period, which is the same as that of wintertime SWS. This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind, which simultaneously resembles the North Atlantic Oscillation (NAO) in the overlying atmosphere. As compared with the typical low SWS winters, during the typical high SWS winters, the stratospheric polar night jet (PNJ) is evidently enhanced and extends from the stratosphere to the troposphere, even down to the North Atlantic Ocean surface. Notably, the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere. Thus, it seems that the SW is a possible factor for this North Atlantic SST tripolar mode. The dynamical process of stratosphere-troposphere coupling, together with the global atmospheric electric circuit-cloud microphysical process, probably accounts for the particular downward propagation of the SW signal.

46 CFR 7.30 - New York Harbor, NY.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false New York Harbor, NY. 7.30 Section 7.30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Atlantic Coast § 7.30 New York Harbor, NY. A line drawn from East Rockaway Inlet Breakwater Light to Ambrose Light...

77 FR 55208 - Transcontinental Gas Pipe Line Company, LLC; Notice of Intent To Prepare an Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-07

... Southside Expansion Project (Project) involving construction and operation of facilities by Transcontinental... Beginning at 6:30 p.m., Brian's Restaurant (upstairs room), 625 East Atlantic Ave., South Hill, VA 23970.... The Project would include construction and operation of the following facilities: Approximately 91.4...

Child Maltreatment among U.S. East Coast Migrant Farm Workers.

ERIC Educational Resources Information Center

Larson, Oscar W., III; And Others

1987-01-01

Responses of 1,328 educational personnel in 14 states along the Atlantic coastal region who work with migrant children indicated that the incidence of child abuse among migrant families was perceived to be substantially higher than for the general population or nonmigrant families of the same socioeconomic status. (Author/DB)

33 CFR 80.125 - Marblehead Neck, MA to Nahant, MA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Marblehead Neck, MA to Nahant, MA... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.125 Marblehead Neck, MA to Nahant, MA. The 72 COLREGS apply on the harbors, bays, and inlets on the east coast of Massachusetts from...

33 CFR 80.125 - Marblehead Neck, MA to Nahant, MA.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Marblehead Neck, MA to Nahant, MA... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.125 Marblehead Neck, MA to Nahant, MA. The 72 COLREGS apply on the harbors, bays, and inlets on the east coast of Massachusetts from...

33 CFR 80.125 - Marblehead Neck, MA to Nahant, MA.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Marblehead Neck, MA to Nahant, MA... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.125 Marblehead Neck, MA to Nahant, MA. The 72 COLREGS apply on the harbors, bays, and inlets on the east coast of Massachusetts from...

33 CFR 80.125 - Marblehead Neck, MA to Nahant, MA.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Marblehead Neck, MA to Nahant, MA... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.125 Marblehead Neck, MA to Nahant, MA. The 72 COLREGS apply on the harbors, bays, and inlets on the east coast of Massachusetts from...

33 CFR 80.125 - Marblehead Neck, MA to Nahant, MA.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Marblehead Neck, MA to Nahant, MA... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.125 Marblehead Neck, MA to Nahant, MA. The 72 COLREGS apply on the harbors, bays, and inlets on the east coast of Massachusetts from...

MTSAT: Full Disk - NOAA GOES Geostationary Satellite Server

Science.gov Websites

GOES Himawari-8 Indian Ocean Meteosat HEMISPHERIC GOES Atlantic Source | Local GOES West Himawari-8 Meteosat CONTINENTAL PACUS CONUS Source | Local REGIONAL GOES-West Northwest West Central Southwest GOES -East Regional Page Source | Local Pacific Northwest Source | Local Northern Rockies Source | Local

33 CFR 80.135 - Hull, MA to Race Point, MA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Hull, MA to Race Point, MA. 80... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.135 Hull, MA to Race Point, MA. (a... the east coast of Massachusetts from the easternmost radio tower at Hull, charted in approximate...

Student Satisfaction with International Student Support Services at a Mid-Atlantic University

ERIC Educational Resources Information Center

Yobol, Jean Paul

2014-01-01

This study investigated the level of satisfaction that international students experienced with student support services at a liberal arts University in the North East. The University's International Students Services Office (ISSO) is the sole point of contact for students studying under an F1 VISA. Services offered range from government…

33 CFR 167.250 - In the approaches to the Cape Fear River: General.

Code of Federal Regulations, 2012 CFR

2012-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.250 In the approaches to the Cape Fear River: General. The traffic separation scheme (TSS) in the approaches to the Cape Fear River...

33 CFR 167.250 - In the approaches to the Cape Fear River: General.

Code of Federal Regulations, 2013 CFR

2013-07-01

... HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.250 In the approaches to the Cape Fear River: General. The traffic separation scheme (TSS) in the approaches to the Cape Fear River...

33 CFR 167.252 - In the approaches to the Cape Fear River: Traffic separation scheme.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Fear River: Traffic separation scheme. 167.252 Section 167.252 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.252 In the approaches to the Cape Fear River: Traffic separation scheme. (a) A traffic separation...

33 CFR 167.252 - In the approaches to the Cape Fear River: Traffic separation scheme.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Fear River: Traffic separation scheme. 167.252 Section 167.252 Navigation and Navigable Waters COAST... SEPARATION SCHEMES Description of Traffic Separation Schemes and Precautionary Areas Atlantic East Coast § 167.252 In the approaches to the Cape Fear River: Traffic separation scheme. (a) A traffic separation...